🏷️ Type Annotation Guide

How to properly annotate types in Python, to make your editor and linters happy and better auto-complete while coding.

Basic types

TODO: Refine this

• str
• int
• float
• bool
• list
• tuple
• dict
• set
• None
• Any
• Union
• Optional
• Callable
• Iterable
• Iterator
• Generator
• Sequence
• Mapping
• Type
• Tuple
• List
• Dict

Optional parameters

• Python 3.10+: SomeType | None
• Python 3.9 and below: Union[SomeType, None]

Class

class MyClass:
    def __init__(self, name: str) -> None:
        self.name = name

    def say_hello(self, name: str) -> str:
        return f"Hello {name}"