如何使用pyPdf沿中间分割/裁剪pdf

from PyPDF2 import PdfFileReader, PdfFileWriter

def split_pdf(input_path, output_path_1, output_path_2):
    # 打开 PDF 文件
    with open(input_path, 'rb') as file:
        reader = PdfFileReader(file)
        writer_1 = PdfFileWriter()
        writer_2 = PdfFileWriter()

        # 获取 PDF 的总页数
        num_pages = reader.getNumPages()

        # 分割 PDF
        for page_num in range(num_pages):
            page = reader.getPage(page_num)
            if page_num < num_pages // 2:
                writer_1.addPage(page)
            else:
                writer_2.addPage(page)

        # 写入新的 PDF 文件
        with open(output_path_1, 'wb') as output_file_1:
            writer_1.write(output_file_1)
        with open(output_path_2, 'wb') as output_file_2:
            writer_2.write(output_file_2)

# 使用函数分割 PDF
split_pdf('input.pdf', 'output_1.pdf', 'output_2.pdf')