如何使用ReportLab从各种页面模板生成PDF？

Question

我有JSON文件，包含大量数据和4页PDF模板。我需要使用所有这些数据ang页面模板生成单个PDF文件。现在我的代码看起来像这样：

    self.line(self.data['sendr'], 10, 250,
              250, {'min_font': 7, 'max_string': 70})
    self.line(self.data['list_num'], 10, 450,
              25, {'min_font': 7, 'max_string': 70})
    self.line(self.data['send_date'], 10, 250,
              45, {'min_font': 7, 'max_string': 70})
    self.line(self.data['delivery_rate_sum_end'], 10, 450,
              450, {'min_font': 7, 'max_string': 70})

    self.can.save()
    self.packet.seek(0)

    new_pdf = PdfFileReader(self.packet)
    current_folder = os.path.dirname(os.path.abspath(__file__))
    existing_pdf = PdfFileReader(
        file("{0}/original/blank_103_1.pdf".format(current_folder), "rb"))
    output = PdfFileWriter()

    page = existing_pdf.getPage(0)
    page.mergePage(new_pdf.getPage(0))
    output.addPage(page)
    print "Page 1 complete"

    # four row page mail part
    for item in range(3, int(self.data['email_count']) - 2, 4):
        self.line(self.data['sends'][item]['rcpn'], 10, 350,
                  250, {'min_font': 7, 'max_string': 70})
        self.line(self.data['sends'][item]['mail_count'], 10, 450,
                  250)

        new_pdf2 = PdfFileReader(self.packet)
        existing_pdf2 = PdfFileReader(
            file("{0}/original/blank_103_2.pdf".format(current_folder), "rb"))

        page2 = existing_pdf2.getPage(0)
        page2.mergePage(new_pdf2.getPage(0))
        output.addPage(page2)
        print "Page ", item, " complete"

    # last page part
    self.line(self.data['sendr'], 10, 100,
              25, {'min_font': 7, 'max_string': 70})
    self.line(self.data['list_num'], 10, 70,
              45, {'min_font': 7, 'max_string': 70})
    self.line(self.data['send_date'], 10, 150,
              45, {'min_font': 7, 'max_string': 70})
    self.line(self.data['delivery_rate_sum_end'], 10, 450,
              450, {'min_font': 7, 'max_string': 70})

    new_pdf1 = PdfFileReader(self.packet)
    existing_pdf1 = PdfFileReader(
        file("{0}/original/blank_103_4.pdf".format(current_folder), "rb"))

    page1 = existing_pdf1.getPage(0)
    page1.mergePage(new_pdf1.getPage(0))
    output.addPage(page1)
    print "Last page complete"

    filename = int(time.time())
    outputStream = file(
        "{0}/pdf/f103/{1}.pdf".format(current_folder, filename), "wb")
    output.write(outputStream)
    outputStream.close()

它会生成一个PDF文件，其中包含所有需要的页面模板，但在所有页面上生成的数据都是从第一页的部件呈现的。如何仅为每个页面传播数据（某些行为第1页，某些数据为第2,3页，...，n，某些数据为最后一页）？对于以pdf编写，我使用pypdf库。