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| -rw-r--r-- | Doc/library/contextlib.rst | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/Doc/library/contextlib.rst b/Doc/library/contextlib.rst index 54d3a8e..0b1f4f7 100644 --- a/Doc/library/contextlib.rst +++ b/Doc/library/contextlib.rst @@ -152,10 +152,22 @@ Functions and classes provided: .. function:: nullcontext(enter_result=None) - Return a context manager that returns enter_result from ``__enter__``, but + Return a context manager that returns *enter_result* from ``__enter__``, but otherwise does nothing. It is intended to be used as a stand-in for an optional context manager, for example:: + def myfunction(arg, ignore_exceptions=False): + if ignore_exceptions: + # Use suppress to ignore all exceptions. + cm = contextlib.suppress(Exception) + else: + # Do not ignore any exceptions, cm has no effect. + cm = contextlib.nullcontext() + with cm: + # Do something + + An example using *enter_result*:: + def process_file(file_or_path): if isinstance(file_or_path, str): # If string, open file |