'Returns an iterator that provides data in the region chrom:start-end'

def get_iterator(self, data_file, chrom, start, end, **kwargs):

    chrom = str(chrom)
    start = int(start)
    end = int(end)
    try:
        data = data_file.fetch(start=start, end=end, reference=chrom)
    except ValueError:
        chrom = _convert_between_ucsc_and_ensemble_naming(chrom)
        try:
            data = data_file.fetch(start=start, end=end, reference=chrom)
        except ValueError:
            return None
    return data
