使用PyPdf2替换pdf中的文本

import PyPDF2

pdf_file = open('example.pdf', 'rb')

pdf_reader = PyPDF2.PdfReader(pdf_file)

num_pages = pdf_reader.numPages

pdf_writer = PyPDF2.PdfWriter()

for page_num in range(num_pages):
    page = pdf_reader.getPage(page_num)
    text = page.extractText()
    new_text = text.replace('old_text', 'new_text')
    page.mergePage(new_text)
    pdf_writer.addPage(page)

output_file = open('output.pdf', 'wb')
pdf_writer.write(output_file)
output_file.close()