Add docstring

IPython/utils/tempdir.py

@@ -1,54 +1,60 b''
+""" This module contains classes - NamedFileInTemporaryDirectory, TemporaryWorkingDirectory.
+
+These classes add extra features such as creating a named file in temporary directory and 
+creating a context manager for the working directory which is also temporary.
+"""
+
 import os as _os
 import warnings as _warnings
 import sys as _sys
 
 from tempfile import TemporaryDirectory
 
 class NamedFileInTemporaryDirectory(object):
 
     def __init__(self, filename, mode='w+b', bufsize=-1, **kwds):
         """
         Open a file named `filename` in a temporary directory.
 
         This context manager is preferred over `NamedTemporaryFile` in
         stdlib `tempfile` when one needs to reopen the file.
 
         Arguments `mode` and `bufsize` are passed to `open`.
         Rest of the arguments are passed to `TemporaryDirectory`.
 
         """
         self._tmpdir = TemporaryDirectory(**kwds)
         path = _os.path.join(self._tmpdir.name, filename)
         self.file = open(path, mode, bufsize)
 
     def cleanup(self):
         self.file.close()
         self._tmpdir.cleanup()
 
     __del__ = cleanup
 
     def __enter__(self):
         return self.file
 
     def __exit__(self, type, value, traceback):
         self.cleanup()
 
 
 class TemporaryWorkingDirectory(TemporaryDirectory):
     """
     Creates a temporary directory and sets the cwd to that directory.
     Automatically reverts to previous cwd upon cleanup.
     Usage example:
 
         with TemporaryWorkingDirectory() as tmpdir:
             ...
     """
     def __enter__(self):
         self.old_wd = _os.getcwd()
         _os.chdir(self.name)
         return super(TemporaryWorkingDirectory, self).__enter__()
 
     def __exit__(self, exc, value, tb):
         _os.chdir(self.old_wd)
         return super(TemporaryWorkingDirectory, self).__exit__(exc, value, tb)