def assert_valid_value(value)
      unless valid?(value)
        raise Property::InvalidValueError.new(self,value)
      end
      true
    end
def assert_valid_value(value)
      unless valid?(value)
        raise Property::InvalidValueError.new(self,value)
      end
      true
    end
Asserts value is valid

 @param [Object] loaded_value
   the value to be tested

 @return [Boolean]
   true if the value is valid

 @raise [Property::InvalidValueError]
   if value is not valid