Move aidge_core.export -> aidge_core.export_utils

aidge_core/__init__.py

@@ -8,6 +8,6 @@ http://www.eclipse.org/legal/epl-2.0.
 SPDX-License-Identifier: EPL-2.0
 """
 from aidge_core.aidge_core import * # import so generated by PyBind
-from aidge_core.export import ExportNode, generate_file, generate_str
+from aidge_core.export_utils import ExportNode, generate_file, generate_str
 import aidge_core.utils
 from aidge_core.aidge_export_aidge import *