chore: add a metaclass resolver

backend/geonature/core/gn_synthese/module.py

@@ -1,13 +1,10 @@
 from geonature.core.gn_commons.models import TModules
 
 from geonature.core.gn_synthese.imports import SyntheseImportMixin
+from geonature.utils.metaclass_utils import metaclass_resolver
 
 
-class SyntheseModuleMetaclass(type(SyntheseImportMixin), type(TModules)):
-    pass
-
-
-class SyntheseModule(TModules, SyntheseImportMixin, metaclass=SyntheseModuleMetaclass):
+class SyntheseModule(metaclass_resolver(TModules, SyntheseImportMixin)):
     __mapper_args__ = {"polymorphic_identity": "synthese"}
 
     def generate_input_url_for_dataset(self, dataset):

backend/geonature/utils/metaclass_utils.py

@@ -0,0 +1,8 @@
+def metaclass_resolver(*classes):
+    metaclass = tuple(set(type(cls) for cls in classes))
+    metaclass = (
+        metaclass[0]
+        if len(metaclass) == 1
+        else type("_".join(mcls.__name__ for mcls in metaclass), metaclass, {})
+    )
+    return metaclass("_".join(cls.__name__ for cls in classes), classes, {})

contrib/gn_module_occhab/backend/gn_module_occhab/module.py

@@ -1,13 +1,10 @@
 from geonature.core.gn_commons.models import TModules
+from geonature.utils.metaclass_utils import metaclass_resolver
 
 from .imports import OcchabImportMixin
 
 
-class OcchabModuleMetaclass(type(OcchabImportMixin), type(TModules)):
-    pass
-
-
-class OcchabModule(TModules, OcchabImportMixin, metaclass=OcchabModuleMetaclass):
+class OcchabModule(metaclass_resolver(TModules, OcchabImportMixin)):
     __mapper_args__ = {"polymorphic_identity": "occhab"}
 
     def generate_input_url_for_dataset(self, dataset):