code: def execute(self, command, params):
          
          command_info = self._commands[command]
          assert command_info is not None, 'Unrecognised command %s' % command
          path = string.Template(command_info[1]).substitute(params)
          if hasattr(self, 'w3c') and self.w3c and isinstance(params, dict) and 'sessionId' in params:
              del params['sessionId']
          data = utils.dump_json(params)
          url = '%s%s' % (self._url, path)
          return self._request(command_info[0], url, body=data)
docs: Send a command to the remote server.
  
          Any path subtitutions required for the URL mapped to the command should be
          included in the command parameters.
  
          :Args:
           - command - A string specifying the command to execute.
           - params - A dictionary of named parameters to send with the command as
             its JSON payload.