code: def update_session(self, alias, headers=None, cookies=None):
          
          session = self._cache.switch(alias)
          session.headers = merge_setting(headers, session.headers)
          session.cookies = merge_cookies(session.cookies, cookies)
docs: Update Session Headers: update a HTTP Session Headers
  
          ``alias`` Robot Framework alias to identify the session
  
          ``headers`` Dictionary of headers merge into session