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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 session(self):
 """ Get session object to benefit from connection pooling. http://docs.python-requests.org/en/master/user/advanced/#session-objects :rtype: requests.Session """

        if self._session is None:
            self._session = requests.Session()
            self._session.headers.update(self._headers)
        return self._session