def p2sh_addr
      return nil unless p2sh?
      hash160 = chunks[1].pushed_data.bth
      return nil unless hash160.htb.bytesize == 20
      Bitcoin.encode_base58_address(hash160, Bitcoin.chain_params.p2sh_version)
    end
def p2sh_addr
      return nil unless p2sh?
      hash160 = chunks[1].pushed_data.bth
      return nil unless hash160.htb.bytesize == 20
      Bitcoin.encode_base58_address(hash160, Bitcoin.chain_params.p2sh_version)
    end
generate p2sh address. if script dose not p2sh, return nil.