How to edit checkboxes in an editable pdf using the python pdfrw library?

I am trying to edit checkboxes on an editable pdf according to user input. I am able to edit text fields using pdfrw as shown here: https://bostata.com/how-to-populate-fillable-pdfs-with-python/

#! /usr/bin/python

import os
import pdfrw


INVOICE_TEMPLATE_PATH = 'invoice_template.pdf'
INVOICE_OUTPUT_PATH = 'invoice.pdf'


ANNOT_KEY = '/Annots'
ANNOT_FIELD_KEY = '/T'
ANNOT_VAL_KEY = '/V'
ANNOT_RECT_KEY = '/Rect'
SUBTYPE_KEY = '/Subtype'
WIDGET_SUBTYPE_KEY = '/Widget'


def write_fillable_pdf(input_pdf_path, output_pdf_path, data_dict):
    template_pdf = pdfrw.PdfReader(input_pdf_path)
    annotations = template_pdf.pages[0][ANNOT_KEY]
    for annotation in annotations:
        if annotation[SUBTYPE_KEY] == WIDGET_SUBTYPE_KEY:
            if annotation[ANNOT_FIELD_KEY]:
                key = annotation[ANNOT_FIELD_KEY][1:-1]
                if key in data_dict.keys():
                    annotation.update(
                        pdfrw.PdfDict(AP=data_dict[key], V=data_dict[key])
                    )
    pdfrw.PdfWriter().write(output_pdf_path, template_pdf)


data_dict = {
   'business_name_1': 'Bostata',
   'customer_name': 'company.io',
   'customer_email': 'joe@company.io',
   'invoice_number': '102394',
   'send_date': '2018-02-13',
   'due_date': '2018-03-13',
   'note_contents': 'Thank you for your business, Joe',
   'item_1': 'Data consulting services',
   'item_1_quantity': '10 hours',
   'item_1_price': '$200/hr',
   'item_1_amount': '$2000',
   'subtotal': '$2000',
   'tax': '0',
   'discounts': '0',
   'total': '$2000',
   'business_name_2': 'Bostata LLC',
   'business_email_address': 'hi@bostata.com',
   'business_phone_number': '(617) 930-4294'
}

if __name__ == '__main__':
    write_fillable_pdf(INVOICE_TEMPLATE_PATH, INVOICE_OUTPUT_PATH, data_dict)

However, I am still having issues with saving the changes to checkbox values. Locally I am able to see the changes on a checkbox in my output file. However when I upload the file to an AWS S3 bucket, the changes are not saved. I am not sure what the issue is. Any help would be appreciated. Thank you!