code: def register(self, command, description, function, params=[]):
          
          return self.app.commands.register(command, description, function, params, self.plugin)
docs: Registers a new command for a plugin.
  
          :param command: Name of the command
          :param description: Description of the command. Is used as help message on cli
          :param function: function reference, which gets invoked if command gets called.
          :param params: list of click options and arguments
          :return: command object