Type System Guides

Contents:

• Typing Python Libraries
  • Why provide type annotations?
  • How to provide type annotations?
  • How much of my library needs types?
  • Best Practices for Inlined Types
  • Compatibility with Older Python Versions
  • Non-Standard Type Behaviors
  • Docstrings
• Writing and Maintaining Stub Files
  • Tools for generating stubs
  • Tools for maintaining stubs
  • Stub Content
  • Common Patterns
  • Style Guide
• Modernizing Superseded Typing Features
  • Introduction
  • Type Comments
  • typing.Text
  • typing.TypedDict Legacy Forms
  • Generics in the typing Module
  • typing.Union and typing.Optional
  • typing.NoReturn
  • Type Aliases
  • User Defined Generics
  • typing.ByteString
  • typing.Hashable and typing.Sized
  • typing.TypeGuard
• Unreachable Code and Exhaustiveness Checking
  • Never and NoReturn
  • assert_never() and Exhaustiveness Checking
  • Marking Code as Unreachable
  • Detecting Unexpectedly Unreachable Code
• Type Narrowing
  • How to use TypeIs and TypeGuard
  • Writing a correct TypeIs function
  • TypeIs and TypeGuard
  • Safety and soundness
  • See also
• Reasons to avoid static type checking
  • Advice for maintainers of untyped libraries