code: def _execute(self, command, data=None, unpack=True):
          
          if not data:
              data = {}
          data.setdefault('element_id', self.element_id)
          return self._driver._execute(command, data, unpack)
docs: Private method to execute command with data.
  
          Args:
              command(Command): The defined command.
              data(dict): The uri variable and body.
  
          Returns:
              The unwrapped value field in the json response.