Added convert.py for storing interfaces

planetmint/backend/convert.py

@@ -0,0 +1,26 @@
+# Copyright © 2020 Interplanetary Database Association e.V.,
+# Planetmint and IPDB software contributors.
+# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
+# Code is Apache-2.0 and docs are CC-BY-4.0
+
+"""Convert interfaces for backends."""
+
+from functools import singledispatch
+
+
+@singledispatch
+def prepare_asset(connection, transaction_type, transaction_id, filter_operation, asset):
+    """
+    This function is used for preparing assets,
+    before storing them to database.
+    """
+    raise NotImplementedError
+
+
+@singledispatch
+def prepare_metadata(connection, transaction_id, metadata):
+    """
+    This function is used for preparing metadata,
+    before storing them to database.
+    """
+    raise NotImplementedError