<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def parse(self):
 """ Run the parse and return the resulting Gff3Set object. """

        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