AttributeError: 'NoneType' object has no attribute 'start'

[crosenth]

av --consensus --reference-top --simchar . --trim-to "1" input.afa

  File "av", line 11, in <module>
    load_entry_point('alnvu==0.3.3', 'console_scripts', 'av')()
  File "lib/python3.6/site-packages/alnvu/av.py", line 263, in main
    reference_top=args.reference_top)
  File "lib/python3.6/site-packages/alnvu/util.py", line 153, in reformat
    start, stop = get_extent(get_seq_from_list(trim_to, seqlist).seq)
  File "lib/python3.6/site-packages/alnvu/util.py", line 69, in get_extent
    start = re.search(r'[a-z]', seqstr, flags=re.I).start()
AttributeError: 'NoneType' object has no attribute 'start'

input.txt

[crosenth]

PR #11