def _get_spades_circular_nodes(self, fastg):
        '''Returns set of names of nodes in SPAdes fastg file that are circular. Names will match those in spades fasta file'''
        seq_reader = pyfastaq.sequences.file_reader(fastg)
        names = set([x.id.rstrip(';') for x in seq_reader if ':' in x.id])
        found_fwd = set()
        found_rev = set()
        for name in names:
            l = name.split(':')
            if len(l) != 2:
                continue
            if l[0] == l[1]:
                if l[0][-1] == "'":
                    found_rev.add(l[0][:-1])
                else:
                    found_fwd.add(l[0])

        return found_fwd.intersection(found_rev)
Returns set of names of nodes in SPAdes fastg file that are circular. Names will match those in spades fasta file