rich error msg for check_consistency

pina/utils.py

@@ -47,15 +47,43 @@ def check_consistency(object_, object_instance, subclass=False):
         object_ = [object_]
 
     for obj in object_:
-        try:
-            if not subclass:
-                assert isinstance(obj, object_instance)
-            else:
-                assert issubclass(obj, object_instance)
-        except AssertionError as e:
-            raise ValueError(
-                f"{type(obj).__name__} must be {object_instance}."
-            ) from e
+        is_class = isinstance(obj, type)
+        expected_type_name = (
+            object_instance.__name__
+            if isinstance(object_instance, type)
+            else str(object_instance)
+        )
+
+        if subclass:
+            if not is_class:
+                raise ValueError(
+                    f"You passed {repr(obj)} "
+                    f"(an instance of {type(obj).__name__}), "
+                    f"but a {expected_type_name} class was expected. "
+                    f"Please pass a {expected_type_name} class or a "
+                    "derived one."
+                )
+            elif not issubclass(obj, object_instance):
+                raise ValueError(
+                    f"You passed {obj.__name__} class, but a "
+                    f"{expected_type_name} class was expected. "
+                    f"Please pass a {expected_type_name} class or a "
+                    "derived one."
+                )
+        else:
+            if is_class:
+                raise ValueError(
+                    f"You passed {obj.__name__} class, but a "
+                    f"{expected_type_name} instance was expected. "
+                    f"Please pass a {expected_type_name} instance."
+                )
+            elif not isinstance(obj, object_instance):
+                raise ValueError(
+                    f"You passed {repr(obj)} "
+                    f"(an instance of {type(obj).__name__}), "
+                    f"but a {expected_type_name} instance was expected. "
+                    f"Please pass a {expected_type_name} instance."
+                )
 
 
 def labelize_forward(forward, input_variables, output_variables):