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#!/usr/bin/env python3
"""Utility functions for dealing with typing."""
import logging
from typing import Any, Optional
logger = logging.getLogger(__name__)
def unwrap_optional(x: Optional[Any]) -> Any:
"""Unwrap an Optional[Type] argument returning a Type value back.
If the Optional[Type] argument is None, however, raise an exception.
Use this to satisfy most type checkers that a value that could
be None isn't so as to drop the Optional typing hint.
>>> x: Optional[bool] = True
>>> unwrap_optional(x)
True
>>> y: Optional[str] = None
>>> unwrap_optional(y)
Traceback (most recent call last):
...
AssertionError: Argument to unwrap_optional was unexpectedly None
"""
if x is None:
msg = 'Argument to unwrap_optional was unexpectedly None'
logger.critical(msg)
raise AssertionError(msg)
return x
if __name__ == '__main__':
import doctest
doctest.testmod()
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