look for NM:i:<N> flag to determine number of mismatches

def count_mismatches(read):
    """
    look for NM:i:<N> flag to determine number of mismatches
    """
    if read is False:
        return False
    mm = [int(i.split(':')[2]) for i in read[11:] if i.startswith('NM:i:')]
    if len(mm) > 0:
        return sum(mm)
    else:
        return False