def data_for_base58check_encoding
      data = BTC::Data.data_from_bytes([self.version]) + @data
      if @public_key_compressed
        data += BTC::Data.data_from_bytes([0x01])
      end
      return data
    end
def data_for_base58check_encoding
      data = BTC::Data.data_from_bytes([self.version]) + @data
      if @public_key_compressed
        data += BTC::Data.data_from_bytes([0x01])
      end
      return data
    end
Usage:
 * WIF.new(string: ...)
 * WIF.new(private_key: ..., public_key_compressed: true|false, network: ...)
 * WIF.new(key: ...)