docs: def hash_and_serialize_chunk(chunk_pii_data,  # type: Sequence[Sequence[str]]
                               keys,  # type: Sequence[Sequence[bytes]]
                               schema  # type: Schema
                               ):
      # type: (...) -> Tuple[List[str], Sequence[int]]
      """
      Generate Bloom filters (ie hash) from chunks of PII then serialize
      the generated Bloom filters. It also computes and outputs the Hamming weight (or popcount) -- the number of bits
      set to one -- of the generated Bloom filters.
  
      :param chunk_pii_data: An iterable of indexable records.
      :param keys: A tuple of two lists of secret keys used in the HMAC.
      :param Schema schema: Schema specifying the entry formats and
              hashing settings.
      :return: A list of serialized Bloom filters and a list of corresponding popcounts
      """
      clk_data = []
      clk_popcounts = []
      for clk in stream_bloom_filters(chunk_pii_data, keys, schema):
          clk_data.append(serialize_bitarray(clk[0]).strip())
          clk_popcounts.append(clk[2])
      return clk_data, clk_popcounts