se adiciona @fields.on_change para ejecutar funcion cuando se cambian los varoles de algun attributo

FossilOrigin-Name: bee19b201f8c1a6b972c2a9abfe5fb57a558a67be6ecddce4f7f07b5b6980215

facho/model/fields/__init__.py

@@ -6,3 +6,15 @@ from .virtual import Virtual
 from .field import Field
 
 __all__ = [Attribute, Many2One, Model, Virtual, Field]
+
+def on_change(fields):
+    from functools import wraps
+    
+    def decorator(func):
+        setattr(func, 'on_changes', fields)
+
+        @wraps(func)
+        def wrapper(self, *arg, **kwargs):
+            return func(self, *arg, **kwargs)
+        return wrapper
+    return decorator