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| -rw-r--r-- | Doc/library/typing.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index e63b839..8f69193 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -2404,6 +2404,13 @@ types. >>> Point3D.__total__ True + This attribute reflects *only* the value of the ``total`` argument + to the current ``TypedDict`` class, not whether the class is semantically + total. For example, a ``TypedDict`` with ``__total__`` set to True may + have keys marked with :data:`NotRequired`, or it may inherit from another + ``TypedDict`` with ``total=False``. Therefore, it is generally better to use + :attr:`__required_keys__` and :attr:`__optional_keys__` for introspection. + .. attribute:: __required_keys__ .. versionadded:: 3.9 @@ -2439,6 +2446,14 @@ types. .. versionadded:: 3.9 + .. note:: + + If ``from __future__ import annotations`` is used or if annotations + are given as strings, annotations are not evaluated when the + ``TypedDict`` is defined. Therefore, the runtime introspection that + ``__required_keys__`` and ``__optional_keys__`` rely on may not work + properly, and the values of the attributes may be incorrect. + See :pep:`589` for more examples and detailed rules of using ``TypedDict``. .. versionadded:: 3.8 |