code: def _session_check(self):
          
          if not os.path.exists(SESSION_FILE):
              self._log.debug("Session file does not exist")
              return False
          with open(SESSION_FILE, 'rb') as f:
              cookies = requests.utils.cookiejar_from_dict(pickle.load(f))
              self._session.cookies = cookies
              self._log.debug("Loaded cookies from session file")
          response = self._session.get(url=self.TEST_URL, headers=self.HEADERS)
          if self.TEST_KEY in str(response.content):
              self._log.debug("Session file appears invalid")
              return False
          self._is_authenticated = True
          self._process_state()
          return True
docs: Attempt to authenticate the user through a session file.
  
          This process is done to avoid having to authenticate the user every
          single time. It uses a session file that is saved when a valid session
          is captured and then reused. Because sessions can expire, we need to
          test the session prior to calling the user authenticated. Right now
          that is done with a test string found in an unauthenticated session.
          This approach is not an ideal method, but it works.