def _xml(t)
      t.adGroupId     @ad_group.id
      t.criterionId   @criterion.id
      t.insertionText @text
      t.paramIndex    @index
    end
def _xml(t)
      t.adGroupId     @ad_group.id
      t.criterionId   @criterion.id
      t.insertionText @text
      t.paramIndex    @index
    end
@private

 adGroupId  	   Id of ad_group This field is required and should not be null.
 criterionId 	 The id of the Keyword criterion that this ad parameter applies to.
                The keyword must be associated with the same ad_group as this AdParam.
                This field is required and should not be null.
 insertionText  Numeric value or currency value (eg. 15, $99.99) to insert into the ad text
                This field is required and should not be null when it is contained
                within Operators : SET. The length of this string should be
                between 1 and 25, inclusive.
 paramIndex