Mock the return value of a mocked method in python

I have a method that I'm trying to test and I would like to mock the methods that my method under test calls. This mocked method calls a method which calls another method and so on. I would like to mock the return value of the top level method, but the return value is lost. I suspect that I am not patching in the right place, but I can't figure out where I should patch. I've read: Where to patch, but I can't tell where I'm going wrong.

The method I'm trying to test is get_url, the first thing it does is create an instance of Bar class. Bar then calls the method I want to mock, get_obj. result should consist of a list of objectLocation objects, each one of which will have a url. However the only thing I get back is a mock object with no return value.

src.delta.FooClass.py

import BarClass

class Foo(object):

    def get_bar(self):
        bar = BarClass.Bar()
        return bar
    
    def get_url(self):
        bar = self.get_bar()
        result = bar.get_obj()
        res = []
        for location in result.objectLocation:
            res.append(location.url)
        return res

src.delta.BarClass.py

class Bar(object):
    
    def get_obj(self):
        return BarObj()
    
class BarObj(object):
    def __init__(self):
        self.objectLocation = []
        for idx in range(0,2):
            loc = BarLocation()
            self.objectLocation.append(loc)

class BarLocation(object):
    def __init__(self):
        self.url = 'www.example.com'

src.test.test_foobar.py

import unittest
import src.delta.FooClass as foo
from mock import patch

class Test(unittest.TestCase):


    def setUp(self):
        self.client = foo.Foo()

    @patch('src.delta.FooClass.BarClass')
    def testName(self,mocked_d1):
        mocked_d1.objectLocation.return_value = ['www.example.com']
        output = self.client.get_url()
        self.assertEqual(['www.example.com','www.example.com'],output)


if __name__ == "__main__":
    unittest.main()