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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 token(self):
 """ obtains a token from the site """

        if self._token is None or \
           datetime.datetime.now() >= self._token_expires_on:
            self._generateForOAuthSecurity(self._client_id,
                                           self._secret_id,
                                           self._token_url)
        return self._token