Type variables with value restriction Type variables with value restriction By default, a type variable can be replaced with any type. However, sometimesit’s useful to have a t...

Creating a stub Creating a stub Here is an overview of how to create a stub file: Write a stub file for the library (or an arbitrary module) and store it asa .pyi file in th...

No errors reported for obviously wrong code No errors reported for obviously wrong code There are several common reasons why obviously wrong code is notflagged as an error. T...

Introduction Getting started Using mypy with an existing codebase

Variance of generic types Variance of generic types There are three main kinds of generic types with respect to subtyperelations between them: invariant, covariant, and contrav...

Typing async/await Typing async/await Mypy supports the ability to type coroutines that use the async/await syntax introduced in Python 3.5. For more information regarding coro...

Getting started Getting started This chapter introduces some core concepts of mypy, including functionannotations, the typing module, library stubs, and more. Be sure to rea...

Defining sub-classes of generic classes Defining sub-classes of generic classes User-defined generic classes and generic classes defined in typing can be used as base classes ...

Casts and type assertions Casts and type assertions Mypy supports type casts that are usually used to coerce a staticallytyped value to a subtype. Unlike languages such as Java...

Final names Syntax variants Details of using Final Final names You can use the typing_extensions.Final qualifier to indicate thata name or attribute should not be reassigned...