enable API use with psycopg 3

nominatim/db/async_core_library.py

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2023 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Import the base libary to use with asynchronous SQLAlchemy.
+"""
+# pylint: disable=invalid-name
+
+from typing import Any
+
+try:
+    import psycopg
+    PGCORE_LIB = 'psycopg'
+    PGCORE_ERROR: Any = psycopg.Error
+except ModuleNotFoundError:
+    import asyncpg
+    PGCORE_LIB = 'asyncpg'
+    PGCORE_ERROR = asyncpg.PostgresError