def _unzip_file(cls, content_type, stream=None, mode=None):
tempfile = NamedTemporaryFile(delete=False)
filename = tempfile.name
kwargs = {'mode': mode} if mode else {}
if stream is not None:
tempfile.write(stream.read())
tempfile.close()
if content_type.endswith('gzip'):
zfile = GzipFile(filename, **kwargs)
else:
zfile = ZipFile(filename, **kwargs)
zfile = zfile.open(zfile.namelist()[0])
return zfile
