code: def fromfile(cls, f):
          
          filter = cls()
          filter._setup(*unpack(cls.FILE_FMT, f.read(calcsize(cls.FILE_FMT))))
          nfilters, = unpack(b'<l', f.read(calcsize(b'<l')))
          if nfilters > 0:
              header_fmt = b'<' + b'Q'*nfilters
              bytes = f.read(calcsize(header_fmt))
              filter_lengths = unpack(header_fmt, bytes)
              for fl in filter_lengths:
                  filter.filters.append(BloomFilter.fromfile(f, fl))
          else:
              filter.filters = []
  
          return filter
docs: Deserialize the ScalableBloomFilter in file object `f'.