code: def _build_int_array_el(el_name, parent, list_):
      
      el = parent.add_child(el_name)
      el.add_attribute('xmlns:soapenc',
                       'http://schemas.xmlsoap.org/soap/encoding/')
      el.add_attribute('xsi:type', 'soapenc:Array')
      el.add_attribute('soapenc:arrayType', 'xsd:int[{:d}]'.format(len(list_)))
      for item in list_:
          item_el = el.add_child('item', str(item))
          item_el.add_attribute('xsi:type', 'xsd:int')
      return el
docs: build a soapenc:Array made of ints called `el_name` as a child
      of `parent`