How to unit test a logging message logged in another function Python?

I'm trying to unit test a logging error message called in one function is displayed in another function. I have written unit test for func_a() as below, but do now know how to unit test that func_b() has called logging.error.

Example:

import logging
import unittest

In func.py

def func_a():
    logging.error('error_msg')
    return True


def func_b():
    result = func_a()
    return result

@patch('func.logging')
class Test(unittest.TestCase):
    def test_func_a(self, mock_logging):
        from func import func_a
        mock_logging.error.assert_called_with('error_msg')

How do I write unit test for func_b() that it displays the 'error_msg'?

Appreciate any help!!