docs: def get_cached_token(self):
          ''' Gets a cached auth token
          '''
          token_info = None
          if self.cache_path:
              try:
                  f = open(self.cache_path)
                  token_info_string = f.read()
                  f.close()
                  token_info = json.loads(token_info_string)
  
                  if self.is_token_expired(token_info):
                      token_info = self.refresh_access_token(token_info['refresh_token'])
  
              except IOError:
                  pass
          return token_info