code: def huffman_conv2bitstring(cls, s):
          # type: (str) -> Tuple[int, int]
          
          i = 0
          ibl = len(s) * 8
          for c in s:
              i = (i << 8) + orb(c)
  
          ret = i, ibl
          assert(ret[0] >= 0)
          assert(ret[1] >= 0)
          return ret
docs: huffman_conv2bitstring converts a string into its bitstring
          representation. It returns a tuple: the bitstring and its bitlength.
          This function DOES NOT compress/decompress the string!
  
          @param str s: the bytestring to convert.
          @return (int, int): the bitstring of s, and its bitlength.
          @raise AssertionError