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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 check_output(self, cmd, timeout=None, keep_rc=False, env=None):
 """ Subclasses can override to provide special environment setup, command prefixes, etc. """

        return subproc.call(cmd, timeout=timeout or self.timeout,
                keep_rc=keep_rc, env=env)