os.environ.copy()['COPY_HUH'] = "not really"

[Jeff Epler]

Under Python2.1 and earlier (back to 1.5.2):
>>> import os
>>> os.environ.copy()['COPY_HUH'] = "not really"
>>> print os.environ['COPY_HUH']
not really

Under even 2.3a0 (CVS):
>>> import os
>>> os.environ.copy()['COPY_HUH'] = "not really"
>>> os.system("echo $COPY_HUH")
not really
0

My expectation is that modifying a copy of os.environ would not actually
modify the environment either in the current session or for children
created with os.system ...

dict(os.environ) seems to be the trick on versions of Python that have
it, os.environ.data on versions that don't.

Jeff