code: def a2b_hashed_base58(s):
      
      data = a2b_base58(s)
      data, the_hash = data[:-4], data[-4:]
      if double_sha256(data)[:4] == the_hash:
          return data
      raise EncodingError("hashed base58 has bad checksum %s" % s)
docs: If the passed string is hashed_base58, return the binary data.
      Otherwise raises an EncodingError.