feat: add client_options support for api endpoint override (#829)

* feat: add client_options support for api endpoint override
* chore: replace all `assertEquals` with `assertEqual`
diff --git a/tests/test_http.py b/tests/test_http.py
index 2bf5060..ce27e2e 100644
--- a/tests/test_http.py
+++ b/tests/test_http.py
@@ -1122,7 +1122,7 @@
 
     def test_id_to_from_content_id_header(self):
         batch = BatchHttpRequest()
-        self.assertEquals("12", batch._header_to_id(batch._id_to_header("12")))
+        self.assertEqual("12", batch._header_to_id(batch._id_to_header("12")))
 
     def test_invalid_content_id_header(self):
         batch = BatchHttpRequest()
@@ -1646,7 +1646,7 @@
     def test_build_http_default_timeout_can_be_set_to_zero(self):
         socket.setdefaulttimeout(0)
         http = build_http()
-        self.assertEquals(http.timeout, 0)
+        self.assertEqual(http.timeout, 0)
     
     def test_build_http_default_308_is_excluded_as_redirect(self):
         http = build_http()