docs: def get_specidentitem_percolator_data(item, xmlns):
      """Loop through SpecIdentificationItem children. Find
      percolator data by matching to a dict lookup. Return a
      dict containing percolator data"""
      percomap = {'{0}userParam'.format(xmlns): PERCO_HEADERMAP, }
      percodata = {}
      for child in item:
          try:
              percoscore = percomap[child.tag][child.attrib['name']]
          except KeyError:
              continue
          else:
              percodata[percoscore] = child.attrib['value']
      outkeys = [y for x in list(percomap.values()) for y in list(x.values())]
      for key in outkeys:
          try:
              percodata[key]
          except KeyError:
              percodata[key] = 'NA'
      return percodata