code: def claim_keys(self, key_request, timeout=None):
          
          content = {"one_time_keys": key_request}
          if timeout:
              content["timeout"] = timeout
          return self._send("POST", "/keys/claim", content=content)
docs: Claims one-time keys for use in pre-key messages.
  
          Args:
              key_request (dict): The keys to be claimed. Format should be
                  <user_id>: { <device_id>: <algorithm> }.
              timeout (int): Optional. The time (in milliseconds) to wait when
                  downloading keys from remote servers.