how to create a new layer

[liucuicui0000]

code are as follows. The result file can not be open by photoshop.
I want to know how to create a new layer.

DATA_PATH = os.path.join(os.path.dirname(__file__), 'psd_files')
filename = os.path.join(DATA_PATH, 'test.psd')
with open(filename, 'rb') as fd:
    psd = pytoshop.PsdFile.read(fd)

    first_layer = psd.layer_and_mask_info.layer_info.layer_records[0]
    second_layer = psd.layer_and_mask_info.layer_info.layer_records[1]
    third_layer = first_layer
    psd.layer_and_mask_info.layer_info.layer_records.append(third_layer)
    tmp_name = '1_result' + '.psd'
    with open(tmp_name, 'wb') as fd:
        psd.write(fd)