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"""Backwards compatibility - we use contextlib.nested to support Python 2.6,

but it's removed in Python 3.2."""

# TODO : Remove this once we drop support for Python 2.6, and use

# "with a, b:" instead.

import sys

from contextlib import contextmanager

@contextmanager

def nested(*managers):

"""Combine multiple context managers into a single nested context manager.

This function has been deprecated in favour of the multiple manager form

of the with statement.

The one advantage of this function over the multiple manager form of the

with statement is that argument unpacking allows it to be

used with a variable number of context managers as follows::

with nested(*managers):

do_something()

"""

exits = []

vars = []

exc = (None, None, None)

try:

for mgr in managers:

exit = mgr.__exit__

enter = mgr.__enter__

vars.append(enter())

exits.append(exit)

yield vars

except:

exc = sys.exc_info()

finally:

while exits:

exit = exits.pop()

try:

if exit(*exc):

exc = (None, None, None)

except:

exc = sys.exc_info()

if exc != (None, None, None):

# Don't rely on sys.exc_info() still containing

# the right information. Another exception may

# have been raised and caught by an exit method

raise exc[0], exc[1], exc[2]