code: func (t Type) SingleInheritance() (string, bool) {
  	if t.IsJSONType() {
  		return "", false
  	}
  	tStr := t.TypeString()
  	if tStr == "object" {
  		return "", false
  	}
  	_, ok := scalarTypes[tStr]
  	if ok {
  		return "", false
  	}
  	_, isMultiple := t.MultipleInheritance()
  	return tStr, !isMultiple
  }
docs: // SingleInheritance returns true if it
  // inherit from single object which is not:
  // - basic/scalar type
  // - object