Python 3.7+contextlibterm

contextlib.AbstractAsyncContextManager

protocols

The ABC for async context managers (the __aenter__/__aexit__ protocol).

Syntax

class C(contextlib.AbstractAsyncContextManager): ...

You rarely need to inherit from it: the subclass check is structural, based on __aenter__ and __aexit__ being present, so a suitable class already counts — the ABC mostly serves as a ready base (it supplies an __aenter__ returning self) and as a type annotation. That check only looks at method names, not at whether they are actually coroutines. Added in Python 3.7, and subscriptable for generics since 3.9.

Examples

import contextlib
class ACM:
    async def __aenter__(self): return self
    async def __aexit__(self, *a): return False
print(issubclass(ACM, contextlib.AbstractAsyncContextManager))   # → True

See also

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