code: def count_mismatches(read):
      
      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
docs: look for NM:i:<N> flag to determine number of mismatches