diff --git a/src/music_kraken/objects/collection.py b/src/music_kraken/objects/collection.py
index 700d961..8ec764a 100644
--- a/src/music_kraken/objects/collection.py
+++ b/src/music_kraken/objects/collection.py
@@ -1,4 +1,4 @@
-from typing import List
+from typing import List, Iterable
 
 from .source import SourceAttribute
 from ..utils import string_processing
@@ -60,7 +60,7 @@ class Collection:
         if unified in self._by_attribute[name]:
             return self._by_attribute[name][unified]
 
-    def append(self, element: SourceAttribute, merge_on_conflict: bool = True):
+    def append(self, element, merge_on_conflict: bool = True):
         if type(element) is not self.element_type and self.element_type is not None:
             raise TypeError(f"{type(element)} is not the set type {self.element_type}")
 
@@ -76,6 +76,10 @@ class Collection:
         self._data.append(element)
         self.map_element(element)
 
+    def extend(self, element_list: Iterable, merge_on_conflict: bool = True):
+        for element in element_list:
+            self.append(element, merge_on_conflict=merge_on_conflict)
+
     def __iter__(self):
         for element in self._data:
             yield element
diff --git a/src/music_kraken/objects/parents.py b/src/music_kraken/objects/parents.py
index 74819ff..8110173 100644
--- a/src/music_kraken/objects/parents.py
+++ b/src/music_kraken/objects/parents.py
@@ -25,7 +25,19 @@ class DatabaseObject:
         self.dynamic = dynamic
         
     def merge(self, other, override: bool = False):
-        for collection in 
+        if type(other) != type(self):
+            LOGGER.warning(f"can't merge \"{type(other)}\" into \"{type(self)}\"")
+            return
+
+        for collection in type(self).COLLECTION_ATTRIBUTES:
+            getattr(self, collection).extend(collection)
+
+        for simple_attribute in type(self).SIMPLE_ATTRIBUTES:
+            if getattr(other, simple_attribute) is None:
+                continue
+
+            if override or getattr(self, simple_attribute) is None:
+                setattr(self, simple_attribute, getattr(other, simple_attribute))
 
 
 class MainObject(DatabaseObject):