code: def serialize_transaction(inputs, outputs, lock_time=0, version=1):
      
  
      # add in the inputs
      serialized_inputs = ''.join([serialize_input(input) for input in inputs])
  
      # add in the outputs
      serialized_outputs = ''.join([serialize_output(output) for output in outputs])
  
      return ''.join([
          # add in the version number
          hexlify(struct.pack('<I', version)),
          # add in the number of inputs
          hexlify(variable_length_int(len(inputs))),
          # add in the inputs
          serialized_inputs,
          # add in the number of outputs
          hexlify(variable_length_int(len(outputs))),
          # add in the outputs
          serialized_outputs,
          # add in the lock time
          hexlify(struct.pack('<I', lock_time)),
      ])
docs: Serializes a transaction.