a shortened version of Lib/test/script_helper.py.

Merged revisions 86395 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r86395 | antoine.pitrou | 2010-11-10 14:55:25 +0100 (mer., 10 nov. 2010) | 4 lines

  Issue #10372: Import the warnings module only after the IO library is
  initialized, so as to avoid bootstrap issues with the '-W' option.
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