code: func (c *CSS) AddRule(styleSheetId string, ruleText string, location *CSSSourceRange) (*CSSCSSRule, error) {
  	var v CSSAddRuleParams
  	v.StyleSheetId = styleSheetId
  	v.RuleText = ruleText
  	v.Location = location
  	return c.AddRuleWithParams(&v)
  }
docs: // AddRule - Inserts a new rule with the given `ruleText` in a stylesheet with given `styleSheetId`, at the position specified by `location`.
  // styleSheetId - The css style sheet identifier where a new rule should be inserted.
  // ruleText - The text of a new rule.
  // location - Text position of a new rule in the target style sheet.
  // Returns -  rule - The newly created rule.