learn-python

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"""Function Annotations.
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@see: https://docs.python.org/3/tutorial/controlflow.html#function-annotations
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Function annotations are completely optional metadata information about the types used
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by user-defined functions.
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Annotations are stored in the __annotations__ attribute of the function as a dictionary and have no
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effect on any other part of the function. Parameter annotations are defined by a colon after the
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parameter name, followed by an expression evaluating to the value of the annotation. Return
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annotations are defined by a literal ->, followed by an expression, between the parameter list and
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the colon denoting the end of the def statement.
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"""
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def breakfast(ham: str, eggs: str = 'eggs') -> str:
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    """Breakfast creator.
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    This function has a positional argument, a keyword argument, and the return value annotated.
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    """
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    return ham + ' and ' + eggs
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def test_function_annotations():
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    """Function Annotations."""
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    assert breakfast.__annotations__ == {'eggs': str, 'ham': str, 'return': str}
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