How to fetch Total No of pages count in Python-docx?

Question

I am learning Python-docx and I am using this solution to add page number as given on stackoverflow by @Utkarsh Dalal

def create_element(name):
    return OxmlElement(name)


def create_attribute(element, name, value):
    element.set(nsqn(name), value)


def add_page_number(paragraph):
    paragraph.alignment = WD_PARAGRAPH_ALIGNMENT.CENTER

    page_run = paragraph.add_run()
    t1 = create_element('w:t')
    create_attribute(t1, 'xml:space', 'preserve')
    t1.text = 'Page '
    page_run._r.append(t1)

    page_num_run = paragraph.add_run()

    fldChar1 = create_element('w:fldChar')
    create_attribute(fldChar1, 'w:fldCharType', 'begin')

    instrText = create_element('w:instrText')
    create_attribute(instrText, 'xml:space', 'preserve')
    instrText.text = "PAGE"

    fldChar2 = create_element('w:fldChar')
    create_attribute(fldChar2, 'w:fldCharType', 'end')

    page_num_run._r.append(fldChar1)
    page_num_run._r.append(instrText)
    page_num_run._r.append(fldChar2)

    of_run = paragraph.add_run()
    t2 = create_element('w:t')
    create_attribute(t2, 'xml:space', 'preserve')
    t2.text = ' of '
    of_run._r.append(t2)

    fldChar3 = create_element('w:fldChar')
    create_attribute(fldChar3, 'w:fldCharType', 'begin')

    instrText2 = create_element('w:instrText')
    create_attribute(instrText2, 'xml:space', 'preserve')
    instrText2.text = "NUMPAGES"

    fldChar4 = create_element('w:fldChar')
    create_attribute(fldChar4, 'w:fldCharType', 'end')

    num_pages_run = paragraph.add_run()
    num_pages_run._r.append(fldChar3)
    num_pages_run._r.append(instrText2)
    num_pages_run._r.append(fldChar4)

    for pg in num_pages_run.element:
        print(pg.text)


doc = Document()
add_page_number(doc.sections[0].footer.paragraphs[0])
doc.save("your_doc.docx")

I receive the Page number in format of Page x of y. But when I try to access the value of 'y' for total number of pages, I could not do it. I have tried to access it getting the text attribute of num_pages_run as pg.text. But all I get is NUMPAGES as output instead of number of pages.

I am looking for this feature because I would like to do some actions whenever a new page is added to the document.

Is there a way to get total pages from python-docx or any other alternative?