Jeff Epler's blog

Variations on 'if TYPE_CHECKING'

Suggested by mypy documentation:

from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from typing import …

Works in mypy, pyright, pyrefly. Found in setuptool_scm generated __version__.py:

TYPE_CHECKING = False
if TYPE_CHECKING:
    from typing import …

Works in mypy, pyright, pyrefly. Best variant for CircuitPython?

def const(x): return x
TYPE_CHECKING = const(0)
if TYPE_CHECKING:
    from typing import …

Works in mypy only. Does not work in pyright, pyrefly:

if False:
    from typing import …

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