Interactive(smartform) form PDF calculation not working in pymupdf

[agsdineshDev]

What we were trying to do?

We are trying to fill the interactive form values using the pymupdf widget field and generating a new pdf.

Description of the bug

We are trying to access the field in smart pdf form and fill in the value using the field.field_value. once the update is done, we expect the total field in the pdf to be updated. but that is not working as expected

Sample doc

widgettest12.pdf

To Reproduce, the sample code below

import fitz
doc = fitz.open('widgettest12.pdf')  # new or existing PDF
page = doc[0]
#print (page) 
#page_wid = page.widget()

for field in page.widgets():
    print (field.field_name)
    if (field.field_name == 'num2'):
        field.field_value = '201'
        field.update()

    if (field.field_name == 'num1'):
        field.field_value = '150'
        field.update()
    
    if (field.field_name == 'Text4'):
        field.update()
        #field.script_format
        #field.script_change

#page = doc.reload_page(page)   
doc.save("widgettest_result.pdf")
doc.close()

Screenshots of actual result

Expected behaviour

configuration used

• Operating system : Windows 10
• Python version: 3.10
• PyMuPDF version:1.20.0