code: def bind
        raise ModelNotSetError.new("You must set the model before binding it.") unless @model
  
        fields do |field|
          view_obj = self.view.viewWithTag(field.tag)
          @model.send("#{field.name}=".to_sym, view_obj.text) if view_obj.respond_to?(:text)
        end
      end
docs: +bind+ fetches all mapped fields from
   any subview of the current +UIView+
   and transfers the contents to the
   corresponding fields of the model
   specified by the +model+ method.