def validate
      errors = {}

      call_validators do |name, message|
        errors[name] ||= []
        errors[name] << to_error(message)
      end

      errors
    end
def validate
      errors = {}

      call_validators do |name, message|
        errors[name] ||= []
        errors[name] << to_error(message)
      end

      errors
    end
Validates all properties based on configured validators.

 @return [Hash<Symbol,Array>] map of errors where key is the property name
                              and value is the list of errors
 @see ClassMethods#add_validator