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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 _create_user_agent(self):
 """ Create the user agent and return it as a string. """

        user_agent = '{}/{} {}'.format(pyspacegdn.__title__,
                                       pyspacegdn.__version__,
                                       default_user_agent())
        if self.client_name:
            user_agent = '{}/{} {}'.format(self.client_name,
                                           self.client_version, user_agent)
        return user_agent