diff --git a/dibbler/conf.py b/dibbler/conf.py
index 7cf5c62..b5ad3a5 100644
--- a/dibbler/conf.py
+++ b/dibbler/conf.py
@@ -26,7 +26,7 @@ def default_config_path_submissive_and_readable() -> bool:
 config: dict[str, dict[str, Any]] = {}
 
 
-def load_config(config_path: Path | None = None):
+def load_config(config_path: Path | None = None) -> None:
     global config
     if config_path is not None:
         with Path(config_path).open("rb") as file:
diff --git a/dibbler/lib/helpers.py b/dibbler/lib/helpers.py
index 062535f..650048f 100644
--- a/dibbler/lib/helpers.py
+++ b/dibbler/lib/helpers.py
@@ -14,8 +14,7 @@ from ..models import Product, User
 def search_user(
     string: str,
     sql_session: Session,
-    ignorethisflag=None,
-):
+) -> User | list[User] | None:
     assert sql_session is not None
     string = string.lower()
     exact_match = (
@@ -42,7 +41,7 @@ def search_product(
     string: str,
     sql_session: Session,
     find_hidden_products: bool = True,
-):
+) -> Product | list[Product] | None:
     assert sql_session is not None
     if find_hidden_products:
         exact_match = (
@@ -120,10 +119,10 @@ def guess_data_type(string: str) -> Literal["card", "rfid", "bar_code", "usernam
 
 
 def argmax(
-    d,
+    d: dict[Any, Any],
     all_: bool = False,
     value: Callable[[Any], Any] | None = None,
-):
+) -> Any | list[Any] | None:
     maxarg = None
     if value is not None:
         dd = d
diff --git a/dibbler/lib/statistikkHelpers.py b/dibbler/lib/statistikkHelpers.py
index 4b58e7b..9b74ccb 100644
--- a/dibbler/lib/statistikkHelpers.py
+++ b/dibbler/lib/statistikkHelpers.py
@@ -11,7 +11,7 @@ from ..models import Transaction
 from .helpers import *
 
 
-def getUser(sql_session: Session):
+def getUser(sql_session: Session) -> str:
     assert sql_session is not None
     while 1:
         string = input("user? ")
@@ -39,7 +39,7 @@ def getUser(sql_session: Session):
             return user[n].name
 
 
-def getProduct(sql_session: Session):
+def getProduct(sql_session: Session) -> str:
     assert sql_session is not None
     while 1:
         string = input("product? ")
@@ -90,7 +90,7 @@ class Database:
 
 
 class InputLine:
-    def __init__(self, u, p, t):
+    def __init__(self, u, p, t) -> None:
         self.inputUser = u
         self.inputProduct = p
         self.inputType = t
@@ -123,17 +123,17 @@ def getInputType():
     return int(inp)
 
 
-def getProducts(products):
+def getProducts(products: str) -> list[tuple[str]]:
     product = []
-    products = products.partition("¤")
+    split_products = products.partition("¤")
     product.append(products[0])
     while products[1] == "¤":
-        products = products[2].partition("¤")
+        split_products = split_products[2].partition("¤")
         product.append(products[0])
     return product
 
 
-def getDateFile(date, inp):
+def getDateFile(date: str, inp: str) -> datetime.date:
     try:
         year = inp.partition("-")
         month = year[2].partition("-")
@@ -359,7 +359,7 @@ def buildDatabaseFromFile(inputFile, inputType, inputProduct, inputUser):
     return database, dateLine
 
 
-def printTopDict(dictionary, n, k):
+def printTopDict(dictionary: dict[str, Any], n: int, k: bool) -> None:
     i = 0
     for key in sorted(dictionary, key=dictionary.get, reverse=k):
         print(key, ": ", dictionary[key])
@@ -369,7 +369,7 @@ def printTopDict(dictionary, n, k):
             break
 
 
-def printTopDict2(dictionary, dictionary2, n):
+def printTopDict2(dictionary, dictionary2, n) -> None:
     print("")
     print("product :  price[kr] ( number )")
     i = 0
@@ -381,7 +381,7 @@ def printTopDict2(dictionary, dictionary2, n):
             break
 
 
-def printWeekdays(week, days):
+def printWeekdays(week, days) -> None:
     if week == [] or days == 0:
         return
     print(
@@ -404,10 +404,10 @@ def printWeekdays(week, days):
     print("")
 
 
-def printBalance(database, user):
+def printBalance(database, user) -> None:
     forbruk = 0
     if user in database.personVareVerdi:
-        forbruk = sum(list(database.personVareVerdi[user].values()))
+        forbruk = sum(database.personVareVerdi[user].values())
         print("totalt kjøpt for: ", forbruk, end=" ")
     if user in database.personNegTransactions:
         print("kr, totalt lagt til: ", -database.personNegTransactions[user], end=" ")
@@ -419,14 +419,14 @@ def printBalance(database, user):
     print("")
 
 
-def printUser(database, dateLine, user, n):
+def printUser(database, dateLine, user, n) -> None:
     printTopDict2(database.personVareVerdi[user], database.personVareAntall[user], n)
     print("\nforbruk per ukedag [kr/dag],", end=" ")
     printWeekdays(database.personUkedagVerdi[user], len(dateLine))
     printBalance(database, user)
 
 
-def printProduct(database, dateLine, product, n):
+def printProduct(database, dateLine, product, n) -> None:
     printTopDict(database.varePersonAntall[product], n, 1)
     print("\nforbruk per ukedag [antall/dag],", end=" ")
     printWeekdays(database.vareUkedagAntall[product], len(dateLine))
@@ -440,7 +440,7 @@ def printProduct(database, dateLine, product, n):
     )
 
 
-def printGlobal(database, dateLine, n):
+def printGlobal(database, dateLine, n) -> None:
     print("\nmest lagt til: ")
     printTopDict(database.personNegTransactions, n, 0)
     print("\nmest tatt fra:")
@@ -454,9 +454,9 @@ def printGlobal(database, dateLine, n):
         "Det er solgt varer til en verdi av: ",
         sum(database.globalDatoForbruk),
         "kr, det er lagt til",
-        -sum(list(database.personNegTransactions.values())),
+        -sum(database.personNegTransactions.values()),
         "og tatt fra",
-        sum(list(database.personPosTransactions.values())),
+        sum(database.personPosTransactions.values()),
         end=" ",
     )
     print(
@@ -466,7 +466,7 @@ def printGlobal(database, dateLine, n):
     )
 
 
-def alt4menuTextOnly(database, dateLine, sql_session: Session):
+def alt4menuTextOnly(database, dateLine, sql_session: Session) -> None:
     assert sql_session is not None
     n = 10
     while 1:
@@ -495,7 +495,7 @@ def alt4menuTextOnly(database, dateLine, sql_session: Session):
             n = int(input("set number to show "))
 
 
-def statisticsTextOnly(sql_session: Session):
+def statisticsTextOnly(sql_session: Session) -> None:
     assert sql_session is not None
     inputType = 4
     product = ""
diff --git a/dibbler/main.py b/dibbler/main.py
index 29b923b..b30c810 100644
--- a/dibbler/main.py
+++ b/dibbler/main.py
@@ -28,7 +28,7 @@ subparsers.add_parser("slabbedasker", help="Find out who is slabbedasker")
 subparsers.add_parser("seed-data", help="Fill with mock data")
 
 
-def main():
+def main() -> None:
     args = parser.parse_args()
 
     load_config(args.config)
diff --git a/dibbler/menus/addstock.py b/dibbler/menus/addstock.py
index 52b4090..66c5ea4 100644
--- a/dibbler/menus/addstock.py
+++ b/dibbler/menus/addstock.py
@@ -15,7 +15,7 @@ from .helpermenus import Menu
 
 
 class AddStockMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Add stock and adjust credit", sql_session)
         self.help_text = """
 Enter what you have bought for PVVVV here, along with your user name and how
@@ -116,7 +116,7 @@ much money you're due in credits for the purchase when prompted.\n"""
         thing: User | Product,
         amount: int,
         price: int,
-    ):
+    ) -> None:
         if isinstance(thing, User):
             self.users.append(thing)
         elif thing in list(self.products.keys()):
@@ -126,7 +126,7 @@ much money you're due in credits for the purchase when prompted.\n"""
         else:
             self.products[thing] = [amount, price]
 
-    def perform_transaction(self):
+    def perform_transaction(self) -> None:
         print("Did you pay a different price?")
         if self.confirm(">", default=False):
             self.price = self.input_int("How much did you pay?", 0, self.price, default=self.price)
diff --git a/dibbler/menus/buymenu.py b/dibbler/menus/buymenu.py
index a96738c..fc2d043 100644
--- a/dibbler/menus/buymenu.py
+++ b/dibbler/menus/buymenu.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 import sqlalchemy
 from sqlalchemy.exc import SQLAlchemyError
 from sqlalchemy.orm import Session
@@ -18,7 +20,7 @@ class BuyMenu(Menu):
     superfast_mode: bool
     purchase: Purchase
 
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Buy", sql_session)
         self.superfast_mode = False
         self.help_text = """
@@ -124,7 +126,7 @@ When finished, write an empty line to confirm the purchase.\n"""
         for thing, num in initial_contents:
             self.add_thing_to_purchase(thing, num)
 
-        def is_product(candidate):
+        def is_product(candidate: Any) -> bool:
             return isinstance(candidate[0], Product)
 
         if len(initial_contents) > 0 and all(map(is_product, initial_contents)):
diff --git a/dibbler/menus/editing.py b/dibbler/menus/editing.py
index 8017e44..ccd74f7 100644
--- a/dibbler/menus/editing.py
+++ b/dibbler/menus/editing.py
@@ -17,10 +17,10 @@ __all__ = [
 
 
 class AddUserMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Add user", sql_session)
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
         username = self.input_str(
             "Username (should be same as PVV username)",
@@ -57,7 +57,7 @@ class AddUserMenu(Menu):
 
 
 class EditUserMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Edit user", sql_session)
         self.help_text = """
 The only editable part of a user is its card number and rfid.
@@ -66,7 +66,7 @@ First select an existing user, then enter a new card number for that
 user, then rfid (write an empty line to remove the card number or rfid).
 """
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
         user = self.input_user("User")
         self.printc(f"Editing user {user.name}")
@@ -97,13 +97,17 @@ user, then rfid (write an empty line to remove the card number or rfid).
 
 
 class AddProductMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Add product", sql_session)
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
         bar_code = self.input_str("Bar code", regex=Product.bar_code_re, length_range=(8, 13))
+        assert bar_code is not None
+
         name = self.input_str("Name", regex=Product.name_re, length_range=(1, Product.name_length))
+        assert name is not None
+
         price = self.input_int("Price", 1, 100000)
         product = Product(bar_code, name, price)
         self.sql_session.add(product)
@@ -117,10 +121,10 @@ class AddProductMenu(Menu):
 
 
 class EditProductMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Edit product", sql_session)
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
         product = self.input_product("Product")
         self.printc(f"Editing product {product.name}")
@@ -172,10 +176,10 @@ class EditProductMenu(Menu):
 
 
 class AdjustStockMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Adjust stock", sql_session)
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
         product = self.input_product("Product")
 
@@ -203,10 +207,10 @@ class AdjustStockMenu(Menu):
 
 
 class CleanupStockMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Stock Cleanup", sql_session)
 
-    def _execute(self, **_kwargs):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
 
         products = self.sql_session.query(Product).filter(Product.stock != 0).all()
diff --git a/dibbler/menus/faq.py b/dibbler/menus/faq.py
index 6524a7c..9dfc0c6 100644
--- a/dibbler/menus/faq.py
+++ b/dibbler/menus/faq.py
@@ -4,7 +4,7 @@ from .helpermenus import Menu, MessageMenu
 
 
 class FAQMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Frequently Asked Questions", sql_session)
         self.items = [
             MessageMenu(
diff --git a/dibbler/menus/helpermenus.py b/dibbler/menus/helpermenus.py
index 01bb2a2..ae78e16 100644
--- a/dibbler/menus/helpermenus.py
+++ b/dibbler/menus/helpermenus.py
@@ -1,10 +1,9 @@
+from __future__ import annotations
+
 import re
 import sys
-from collections.abc import Callable, Iterable
 from select import select
-from typing import Any, Literal, Self
-
-from sqlalchemy.orm import Session
+from typing import TYPE_CHECKING, Any, Literal, Self, TypeVar
 
 from dibbler.lib.helpers import (
     argmax,
@@ -14,6 +13,11 @@ from dibbler.lib.helpers import (
 )
 from dibbler.models import Product, User
 
+if TYPE_CHECKING:
+    from collections.abc import Callable, Iterable
+
+    from sqlalchemy.orm import Session
+
 exit_commands: list[str] = ["exit", "abort", "quit", "bye", "eat flaming death", "q"]
 help_commands: list[str] = ["help", "?"]
 context_commands: list[str] = ["what", "??"]
@@ -24,10 +28,13 @@ class ExitMenuException(Exception):
     pass
 
 
+MenuItemType = TypeVar("MenuItemType", bound="Menu")
+
+
 class Menu:
     name: str
     sql_session: Session
-    items: list[Self | tuple | str]
+    items: list[Menu | tuple[MenuItemType, str] | str]
     prompt: str | None
     end_prompt: str | None
     return_index: bool
@@ -41,7 +48,7 @@ class Menu:
         self,
         name: str,
         sql_session: Session,
-        items: list[Self | tuple[Any, str] | str] | None = None,
+        items: list[Self | tuple[MenuItemType, str] | str] | None = None,
         prompt: str | None = None,
         end_prompt: str | None = "> ",
         return_index: bool = True,
@@ -49,7 +56,7 @@ class Menu:
         exit_confirm_msg: str | None = None,
         exit_disallowed_msg: str | None = None,
         help_text: str | None = None,
-    ):
+    ) -> None:
         self.name: str = name
         self.sql_session: Session = sql_session
         self.items = items if items is not None else []
@@ -115,7 +122,7 @@ class Menu:
             return self.items[i][1]
         return self.items[i]
 
-    def item_value(self, i: int):
+    def item_value(self, i: int) -> MenuItemType | int:
         if isinstance(self.items[i], tuple):
             return self.items[i][0]
         if self.return_index:
@@ -127,7 +134,7 @@ class Menu:
         prompt: str | None = None,
         end_prompt: str | None = None,
         regex: str | None = None,
-        length_range=(None, None),
+        length_range: tuple[int | None, int | None] = (None, None),
         empty_string_is_none: bool = False,
         timeout: int | None = None,
         default: str | None = None,
@@ -222,7 +229,7 @@ class Menu:
         number_of_choices: int,
         prompt: str | None = None,
         end_prompt: str | None = None,
-    ):
+    ) -> int:
         while True:
             result = self.input_str(prompt, end_prompt)
             assert result is not None
@@ -238,7 +245,7 @@ class Menu:
                 if not self.special_input_choice(result):
                     self.invalid_menu_choice(result)
 
-    def invalid_menu_choice(self, in_str: str):
+    def invalid_menu_choice(self, in_str: str) -> None:
         print("Please enter a valid choice.")
 
     def input_int(
@@ -317,7 +324,7 @@ class Menu:
         prompt: str | None = None,
         end_prompt: str | None = None,
         permitted_things: Iterable[str] = ("user", "product"),
-        add_nonexisting=(),
+        add_nonexisting: Iterable[str] = (),
         empty_input_permitted: bool = False,
         find_hidden_products: bool = True,
     ) -> User | Product | None:
@@ -340,7 +347,7 @@ class Menu:
         prompt: str | None = None,
         end_prompt: str | None = None,
         permitted_things: Iterable[str] = ("user", "product"),
-        add_nonexisting=(),
+        add_nonexisting: Iterable[str] = (),
         empty_input_permitted: bool = False,
         find_hidden_products: bool = True,
     ) -> tuple[User | Product, int] | None:
@@ -379,8 +386,8 @@ class Menu:
     def search_for_thing(
         self,
         search_str: str,
-        permitted_things=("user", "product"),
-        add_non_existing=(),
+        permitted_things: Iterable[str] = ("user", "product"),
+        add_non_existing: Iterable[str] = (),
         find_hidden_products: bool = True,
     ) -> User | Product | None:
         search_fun = {
@@ -566,15 +573,15 @@ class Menu:
             print(f"Help for {self.header()}:")
             print(self.help_text)
 
-    def execute(self, **kwargs) -> Any:
+    def execute(self, **_kwargs) -> MenuItemType | int | None:
         self.set_context(None)
         try:
-            return self._execute(**kwargs)
+            return self._execute(**_kwargs)
         except ExitMenuException:
             self.at_exit()
             return None
 
-    def _execute(self, **_kwargs) -> Any:
+    def _execute(self, **_kwargs) -> MenuItemType | int | None:
         while True:
             self.print_header()
             self.set_context(None)
@@ -602,7 +609,7 @@ class MessageMenu(Menu):
         message: str,
         sql_session: Session,
         pause_after_message: bool = True,
-    ):
+    ) -> None:
         super().__init__(name, sql_session)
         self.message = message.strip()
         self.pause_after_message = pause_after_message
@@ -623,7 +630,7 @@ class ConfirmMenu(Menu):
         end_prompt: str | None = ": ",
         default: bool | None = None,
         timeout: int | None = 0,
-    ):
+    ) -> None:
         super().__init__(
             "question",
             sql_session,
@@ -657,13 +664,13 @@ class Selector(Menu):
         self,
         name: str,
         sql_session: Session,
-        items=None,
-        prompt="select",
-        return_index=True,
-        exit_msg=None,
-        exit_confirm_msg=None,
-        help_text=None,
-    ):
+        items: list[Self | tuple[MenuItemType, str] | str] | None = None,
+        prompt: str | None = "select",
+        return_index: bool = True,
+        exit_msg: str | None = None,
+        exit_confirm_msg: str | None = None,
+        help_text: str | None = None,
+    ) -> None:
         if items is None:
             items = []
         super().__init__(
@@ -673,6 +680,7 @@ class Selector(Menu):
             prompt,
             return_index=return_index,
             exit_msg=exit_msg,
+            help_text=help_text,
         )
 
     def header(self) -> str:
diff --git a/dibbler/menus/mainmenu.py b/dibbler/menus/mainmenu.py
index 3782e19..9cf7b29 100644
--- a/dibbler/menus/mainmenu.py
+++ b/dibbler/menus/mainmenu.py
@@ -12,15 +12,15 @@ faq_commands = ["faq"]
 restart_commands = ["restart"]
 
 
-def restart():
+def restart() -> None:
     # Does not work if the script is not executable, or if it was
     # started by searching $PATH.
     os.execv(sys.argv[0], sys.argv)
 
 
 class MainMenu(Menu):
-    def __init__(self, sql_session: Session, **kwargs):
-        super().__init__("Dibbler main menu", sql_session, **kwargs)
+    def __init__(self, sql_session: Session, **_kwargs) -> None:
+        super().__init__("Dibbler main menu", sql_session, **_kwargs)
 
     def special_input_choice(self, in_str: str) -> bool:
         mv = in_str.split()
diff --git a/dibbler/menus/miscmenus.py b/dibbler/menus/miscmenus.py
index a05ba57..e6ab769 100644
--- a/dibbler/menus/miscmenus.py
+++ b/dibbler/menus/miscmenus.py
@@ -10,7 +10,7 @@ from .helpermenus import Menu, Selector
 
 
 class TransferMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Transfer credit between users", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -43,7 +43,7 @@ class TransferMenu(Menu):
 
 
 class ShowUserMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Show user", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -124,7 +124,7 @@ class ShowUserMenu(Menu):
 
 
 class UserListMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("User list", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -145,7 +145,7 @@ class UserListMenu(Menu):
 
 
 class AdjustCreditMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Adjust credit", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -176,7 +176,7 @@ class AdjustCreditMenu(Menu):
 
 
 class ProductListMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Product list", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -206,7 +206,7 @@ class ProductListMenu(Menu):
 
 
 class ProductSearchMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Product search", sql_session)
 
     def _execute(self, **_kwargs) -> None:
diff --git a/dibbler/menus/printermenu.py b/dibbler/menus/printermenu.py
index 41aceab..09954c5 100644
--- a/dibbler/menus/printermenu.py
+++ b/dibbler/menus/printermenu.py
@@ -5,7 +5,7 @@ from .helpermenus import Menu
 
 
 class PrintLabelMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Print a label", sql_session)
         self.help_text = """
 Prints out a product bar code on the printer
@@ -13,7 +13,7 @@ Prints out a product bar code on the printer
 Put it up somewhere in the vicinity.
 """
 
-    def _execute(self):
+    def _execute(self, **_kwargs) -> None:
         self.print_header()
 
         print("Printer menu is under renovation, please be patient")
diff --git a/dibbler/menus/stats.py b/dibbler/menus/stats.py
index bcb0995..eeddef2 100644
--- a/dibbler/menus/stats.py
+++ b/dibbler/menus/stats.py
@@ -16,7 +16,7 @@ __all__ = [
 
 
 class ProductPopularityMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Products by popularity", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -49,7 +49,7 @@ class ProductPopularityMenu(Menu):
 
 
 class ProductRevenueMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Products by revenue", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -87,7 +87,7 @@ class ProductRevenueMenu(Menu):
 
 
 class BalanceMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Total balance of PVVVV", sql_session)
 
     def _execute(self, **_kwargs) -> None:
@@ -124,7 +124,7 @@ class BalanceMenu(Menu):
 
 
 class LoggedStatisticsMenu(Menu):
-    def __init__(self, sql_session: Session):
+    def __init__(self, sql_session: Session) -> None:
         super().__init__("Statistics from log", sql_session)
 
     def _execute(self, **_kwargs) -> None:
diff --git a/dibbler/models/Product.py b/dibbler/models/Product.py
index 278ae61..112afe4 100644
--- a/dibbler/models/Product.py
+++ b/dibbler/models/Product.py
@@ -44,7 +44,7 @@ class Product(Base):
         price: int,
         stock: int = 0,
         hidden: bool = False,
-    ):
+    ) -> None:
         self.name = name
         self.bar_code = bar_code
         self.price = price
diff --git a/dibbler/models/Purchase.py b/dibbler/models/Purchase.py
index 81af22a..10259a3 100644
--- a/dibbler/models/Purchase.py
+++ b/dibbler/models/Purchase.py
@@ -34,7 +34,7 @@ class Purchase(Base):
     )
     entries: Mapped[set[PurchaseEntry]] = relationship(back_populates="purchase")
 
-    def __init__(self):
+    def __init__(self) -> None:
         pass
 
     def is_complete(self) -> bool:
diff --git a/dibbler/models/PurchaseEntry.py b/dibbler/models/PurchaseEntry.py
index ad30aa0..7e2d4c0 100644
--- a/dibbler/models/PurchaseEntry.py
+++ b/dibbler/models/PurchaseEntry.py
@@ -31,7 +31,12 @@ class PurchaseEntry(Base):
     product: Mapped[Product] = relationship(back_populates="purchases", lazy="joined")
     purchase: Mapped[Purchase] = relationship(back_populates="entries", lazy="joined")
 
-    def __init__(self, purchase, product, amount):
+    def __init__(
+        self,
+        purchase: Purchase,
+        product: Product,
+        amount: int,
+    ) -> None:
         self.product = product
         self.product_bar_code = product.bar_code
         self.purchase = purchase
diff --git a/dibbler/models/Transaction.py b/dibbler/models/Transaction.py
index 374fe9a..ed5d000 100644
--- a/dibbler/models/Transaction.py
+++ b/dibbler/models/Transaction.py
@@ -45,7 +45,7 @@ class Transaction(Base):
         description: str | None = None,
         purchase: Purchase | None = None,
         penalty: int = 1,
-    ):
+    ) -> None:
         self.user = user
         self.amount = amount
         self.description = description
diff --git a/dibbler/models/User.py b/dibbler/models/User.py
index 2409d8d..1655fb2 100644
--- a/dibbler/models/User.py
+++ b/dibbler/models/User.py
@@ -42,7 +42,7 @@ class User(Base):
         card: str | None,
         rfid: str | None = None,
         credit: int = 0,
-    ):
+    ) -> None:
         self.name = name
         if card == "":
             card = None
@@ -52,8 +52,8 @@ class User(Base):
         self.rfid = rfid
         self.credit = credit
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.name
 
-    def is_anonymous(self):
+    def is_anonymous(self) -> bool:
         return self.card == "11122233"
diff --git a/dibbler/subcommands/loop.py b/dibbler/subcommands/loop.py
index 4278a8c..afe68c7 100755
--- a/dibbler/subcommands/loop.py
+++ b/dibbler/subcommands/loop.py
@@ -43,7 +43,7 @@ from ..menus import (
 random.seed()
 
 
-def main(sql_session: Session):
+def main(sql_session: Session) -> None:
     if not config["general"]["stop_allowed"]:
         set_signal_handler(SIGQUIT, SIG_IGN)
 
diff --git a/dibbler/subcommands/makedb.py b/dibbler/subcommands/makedb.py
index 3280516..edeea69 100644
--- a/dibbler/subcommands/makedb.py
+++ b/dibbler/subcommands/makedb.py
@@ -5,5 +5,5 @@ from sqlalchemy.engine import Engine
 from dibbler.models import Base
 
 
-def main(engine: Engine):
+def main(engine: Engine) -> None:
     Base.metadata.create_all(engine)
diff --git a/dibbler/subcommands/seed_test_data.py b/dibbler/subcommands/seed_test_data.py
index 96b9ef1..9a51991 100644
--- a/dibbler/subcommands/seed_test_data.py
+++ b/dibbler/subcommands/seed_test_data.py
@@ -9,13 +9,13 @@ from dibbler.models.User import User
 JSON_FILE = Path(__file__).parent.parent.parent / "mock_data.json"
 
 
-def clear_db(sql_session: Session):
+def clear_db(sql_session: Session) -> None:
     sql_session.query(Product).delete()
     sql_session.query(User).delete()
     sql_session.commit()
 
 
-def main(sql_session: Session):
+def main(sql_session: Session) -> None:
     clear_db(sql_session)
     product_items = []
     user_items = []
diff --git a/dibbler/subcommands/slabbedasker.py b/dibbler/subcommands/slabbedasker.py
index f668070..cfb7cac 100644
--- a/dibbler/subcommands/slabbedasker.py
+++ b/dibbler/subcommands/slabbedasker.py
@@ -5,7 +5,7 @@ from sqlalchemy.orm import Session
 from dibbler.models import User
 
 
-def main(sql_session: Session):
+def main(sql_session: Session) -> None:
     # Let's find all users with a negative credit
     slabbedasker = sql_session.query(User).filter(User.credit < 0).all()
 
diff --git a/pyproject.toml b/pyproject.toml
index 4d5802d..6bbfdd8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -40,11 +40,12 @@ select = [
     "B", # flake8-bugbear
     "C4", # flake8-comprehensions
     "COM", # flake8-commas
+    "ANN",
     # "E", # pycodestyle
     # "F", # Pyflakes
     "FA", # flake8-future-annotations
     "I", # isort
-    # "S", # flake8-bandit
+    "S", # flake8-bandit
     "ICN", # flake8-import-conventions
     "ISC", # flake8-implicit-str-concat
     # "N", # pep8-naming
@@ -56,6 +57,11 @@ select = [
     "YTT", # flake8-2020
 ]
 ignore = [
-   # line too long
-  "E501",
+  "E501", # line too long
+  "S101", # assert detected
+  "S311", # non-cryptographic random generator
 ]
+
+[tool.ruff.lint.flake8-annotations]
+suppress-dummy-args = true
+ignore-fully-untyped = true