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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def chmod(self, tarinfo, targetpath):
 """Set file permissions of targetpath according to tarinfo. """

        if hasattr(os, 'chmod'):
            try:
                os.chmod(targetpath, tarinfo.mode)
            except EnvironmentError as e:
                raise ExtractError("could not change mode")