def get_id_transcripts(self, hgnc_id, build='<STR_LIT>'):
transcripts = self.transcripts(build=build, hgnc_id=hgnc_id)<EOL>identifier_transcripts = set()<EOL>longest = None<EOL>nr = []<EOL>xm = []<EOL>for tx in transcripts:<EOL><INDENT>enst_id = tx['<STR_LIT>']<EOL>if not longest:<EOL><INDENT>longest = enst_id<EOL><DEDENT>refseq_id = tx.get('<STR_LIT>')<EOL>if not refseq_id:<EOL><INDENT>continue<EOL><DEDENT>if '<STR_LIT>' in refseq_id:<EOL><INDENT>identifier_transcripts.add(enst_id)<EOL><DEDENT>elif '<STR_LIT>' in refseq_id:<EOL><INDENT>nr.append(enst_id)<EOL><DEDENT>elif '<STR_LIT>' in refseq_id:<EOL><INDENT>xm.append(enst_id)<EOL><DEDENT><DEDENT>if identifier_transcripts:<EOL><INDENT>return identifier_transcripts<EOL><DEDENT>if nr:<EOL><INDENT>return set([nr[<NUM_LIT:0>]])<EOL><DEDENT>if xm:<EOL><INDENT>return set([xm[<NUM_LIT:0>]])<EOL><DEDENT>return set([longest])<EOL>
Return a set with identifier transcript(s)

        Choose all refseq transcripts with NM symbols, if none where found choose ONE with NR,
        if no NR choose ONE with XM. If there are no RefSeq transcripts identifiers choose the 
        longest ensembl transcript.

        Args:
            hgnc_id(int)
            build(str)

        Returns:
            identifier_transcripts(set)