Incompatibility with bitarray >= 2.0.0

[arterrey]

Getting an exception using this library...

...
  File "/home/adam/v/tf/evenly/ws2/app/bloom.py", line 25, in get_bloom_filters
    green_bloom = ScalableBloomFilter.fromfile(infile)
  File "/home/adam/v/tf/evenly/ws2/buildout/eggs/pybloom_live-3.0.0-py3.7.egg/pybloom_live/pybloom.py", line 368, in fromfile
    filter.filters.append(BloomFilter.fromfile(f, fl))
  File "/home/adam/v/tf/evenly/ws2/buildout/eggs/pybloom_live-3.0.0-py3.7.egg/pybloom_live/pybloom.py", line 216, in fromfile
    if filter.num_bits != filter.bitarray.length() and \
NotImplementedError: self.length() has been deprecated since 1.5.1, and was removed in 2.0.0.  Use len(self) instead.

I understand that that NotImplementedError comes from bit array, although the trace back doesn't make that super clear - looks like it is from a c file https://github.com/ilanschnell/bitarray/blob/cdb9b11cb144b373f49ac5b5b9015f1bfa2982d7/bitarray/_bitarray.c#L644