def write_disp_units(units, display)
      return unless ptrue?(units)

      attributes = [ ['val', units] ]

      @writer.tag_elements('c:dispUnits') do
        @writer.empty_tag('c:builtInUnit', attributes)
        if ptrue?(display)
          @writer.tag_elements('c:dispUnitsLbl') do
            @writer.empty_tag('c:layout')
          end
        end
     end
    end
def write_disp_units(units, display)
      return unless ptrue?(units)

      attributes = [ ['val', units] ]

      @writer.tag_elements('c:dispUnits') do
        @writer.empty_tag('c:builtInUnit', attributes)
        if ptrue?(display)
          @writer.tag_elements('c:dispUnitsLbl') do
            @writer.empty_tag('c:layout')
          end
        end
     end
    end
Write the <c:dispUnits> element.