add exclude to save_related method, switch to same relation_map from iter

tests/test_utils/test_queryset_utils.py

@@ -4,7 +4,12 @@ import sqlalchemy
 import ormar
 from ormar.models.mixins import ExcludableMixin
 from ormar.queryset.prefetch_query import sort_models
-from ormar.queryset.utils import translate_list_to_dict, update_dict_from_list, update
+from ormar.queryset.utils import (
+    subtract_dict,
+    translate_list_to_dict,
+    update_dict_from_list,
+    update,
+)
 from tests.settings import DATABASE_URL
 
 
@@ -79,6 +84,21 @@ def test_updating_dict_inc_set_with_dict():
     }
 
 
+def test_subtracting_dict_inc_set_with_dict():
+    curr_dict = {
+        "aa": Ellipsis,
+        "bb": Ellipsis,
+        "cc": {"aa": {"xx", "yy"}, "bb": Ellipsis},
+    }
+    dict_to_update = {
+        "uu": Ellipsis,
+        "bb": {"cc", "dd"},
+        "cc": {"aa": {"xx": {"oo": Ellipsis}}, "bb": Ellipsis},
+    }
+    test = subtract_dict(curr_dict, dict_to_update)
+    assert test == {"aa": Ellipsis, "cc": {"aa": {"yy": Ellipsis}}}
+
+
 def test_updating_dict_inc_set_with_dict_inc_set():
     curr_dict = {
         "aa": Ellipsis,
@@ -99,6 +119,23 @@ def test_updating_dict_inc_set_with_dict_inc_set():
     }
 
 
+def test_subtracting_dict_inc_set_with_dict_inc_set():
+    curr_dict = {
+        "aa": Ellipsis,
+        "bb": Ellipsis,
+        "cc": {"aa": {"xx", "yy"}, "bb": Ellipsis},
+        "dd": {"aa", "bb"},
+    }
+    dict_to_update = {
+        "aa": Ellipsis,
+        "bb": {"cc", "dd"},
+        "cc": {"aa": {"xx", "oo", "zz", "ii"}},
+        "dd": {"aa", "bb"},
+    }
+    test = subtract_dict(curr_dict, dict_to_update)
+    assert test == {"cc": {"aa": {"yy"}, "bb": Ellipsis}}
+
+
 database = databases.Database(DATABASE_URL, force_rollback=True)
 metadata = sqlalchemy.MetaData()