Patch method used in global variable in a module in Python

Question

I am trying to mock a method used in a global variable's format method in a module. The file I want to test is as follows:

do_work.py

from foo import bar

LINK = "foobar.com"

def generate_foobar():
    return "visit {}".format(bar(LINK))

FOOBAR = generate_foobar()

The bar function is defined as follows:

foo.py

def bar(link):
    return "<{}>".format(link)

Test is defined as follows:

test_foobar.py

import pytest

from do_work import LINK, generate_foobar

def test_foobar(mocker):
    mocker.patch("do_work.bar", return_value=LINK)
    from do_work import FOOBAR
    expected_value = "visit {}".format(LINK)
    assert generate_foobar() == expected_value # <- this assert passes
    assert FOOBAR == expected_value # <- this assert fails

Even after patching the function bar() the assert with GLOBAL VARIABLE fails. I am not sure why the method used in global variable is not mocked. Is there a way to mock this? Or is it something we can't patch as the function is executed in its own scope then the variable is imported as static value?