code: def CSS_addRule(self, styleSheetId, ruleText, location):
  		
  		assert isinstance(ruleText, (str,)
  		    ), "Argument 'ruleText' must be of type '['str']'. Received type: '%s'" % type(
  		    ruleText)
  		subdom_funcs = self.synchronous_command('CSS.addRule', styleSheetId=
  		    styleSheetId, ruleText=ruleText, location=location)
  		return subdom_funcs
docs: Function path: CSS.addRule
  			Domain: CSS
  			Method name: addRule
  		
  			Parameters:
  				Required arguments:
  					'styleSheetId' (type: StyleSheetId) -> The css style sheet identifier where a new rule should be inserted.
  					'ruleText' (type: string) -> The text of a new rule.
  					'location' (type: SourceRange) -> Text position of a new rule in the target style sheet.
  			Returns:
  				'rule' (type: CSSRule) -> The newly created rule.
  		
  			Description: Inserts a new rule with the given <code>ruleText</code> in a stylesheet with given <code>styleSheetId</code>, at the position specified by <code>location</code>.