docs: def _line_by_type(self, line, header, hgroups, htypes, out, want_type,
                        collapse_quals_fn = None):
          """Parse out key value pairs for line information based on a group of values.
          """
          for index, htype in ((i, t) for i, t in enumerate(htypes) if t == want_type):
              col = hgroups[index][0]
              key = header[col]#self._clean_header(header[col])
              if collapse_quals_fn:
                  val = collapse_quals_fn(line, header, hgroups[index])
              else:
                  val = line[col]
              out[key].add(val)
          return out