code: def parse(self):
          
          fh = self._open()
          try:
              gff3Set = Gff3Set(self.fileName)
              for line in fh:
                  self.lineNumber += 1
                  self._parseLine(gff3Set, line[0:-1])
          finally:
              fh.close()
          gff3Set.linkChildFeaturesToParents()
          return gff3Set
docs: Run the parse and return the resulting Gff3Set object.