Num Intervening does not always produce result

[monprin]

When calling the candidate_genes function with the include_num_intervening option, not all genes will necessarily get this attribute. For instance, when calling with a larger list (from the Sucrose term, in the ZmRoot network in the ZmWallace ontology), this gene:

    {'organism': 'Zea Mays', 'strand': '-', 'num_siblings': 3, 'ID': 'GRMZM2G143499', 'Name': 'GRMZM2G143499', 'biotype': 'protein_coding', 'intervening_rank': 1.0, 'build': '5b', 'parent_locus': '<None>10:145891859-145891859'}

Does not receive the the num_intervening attribute and thus can cause failure.

The relevant section of code can be found in RefGen.py lines 455-468.