如何将文件拆分成相等的部分,而不会破坏单独的行？

def split_file(file_path, num_parts):
    with open(file_path, 'r') as file:
        lines = file.readlines()
        num_lines = len(lines)
        part_size = num_lines // num_parts

        for i in range(num_parts):
            start = i * part_size
            end = (i + 1) * part_size if i < num_parts - 1 else num_lines

            with open(f'{file_path}.part{i + 1}', 'w') as part_file:
                part_file.writelines(lines[start:end])

file_path = 'path/to/your/file.txt'
num_parts = 4
split_file(file_path, num_parts)