[backend][delegates] Update asset model class for assert

beat/editor/backend/delegates.py

@@ -26,7 +26,7 @@
 from PyQt5.QtWidgets import QComboBox
 from PyQt5.QtWidgets import QStyledItemDelegate
 
-from .assetmodel import AssetModel
+from .assetmodel import AbstractAssetModel
 
 
 class AssetItemDelegate(QStyledItemDelegate):
@@ -35,7 +35,7 @@ class AssetItemDelegate(QStyledItemDelegate):
     def __init__(self, asset_model, parent=None):
         super().__init__(parent)
 
-        if not isinstance(asset_model, AssetModel):
+        if not isinstance(asset_model, AbstractAssetModel):
             raise TypeError("Wrong model type")
 
         self.asset_model = asset_model