def evaluate_default_value(val)
      if val.respond_to?(:call)
        val.call
      elsif val.duplicable?
        val.dup
      else
        val
      end
    end
def evaluate_default_value(val)
      if val.respond_to?(:call)
        val.call
      elsif val.duplicable?
        val.dup
      else
        val
      end
    end
Evaluates the default value given, this is used by undump
 when determining the value of the default given for a field options.

 @param [Object] :value the attribute's default value