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venv/lib/python3.10/site-packages/django/db/models/utils.py

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+import functools
+from collections import namedtuple
+
+
+def make_model_tuple(model):
+    """
+    Take a model or a string of the form "app_label.ModelName" and return a
+    corresponding ("app_label", "modelname") tuple. If a tuple is passed in,
+    assume it's a valid model tuple already and return it unchanged.
+    """
+    try:
+        if isinstance(model, tuple):
+            model_tuple = model
+        elif isinstance(model, str):
+            app_label, model_name = model.split(".")
+            model_tuple = app_label, model_name.lower()
+        else:
+            model_tuple = model._meta.app_label, model._meta.model_name
+        assert len(model_tuple) == 2
+        return model_tuple
+    except (ValueError, AssertionError):
+        raise ValueError(
+            "Invalid model reference '%s'. String model references "
+            "must be of the form 'app_label.ModelName'." % model
+        )
+
+
+def resolve_callables(mapping):
+    """
+    Generate key/value pairs for the given mapping where the values are
+    evaluated if they're callable.
+    """
+    for k, v in mapping.items():
+        yield k, v() if callable(v) else v
+
+
+def unpickle_named_row(names, values):
+    return create_namedtuple_class(*names)(*values)
+
+
+@functools.lru_cache
+def create_namedtuple_class(*names):
+    # Cache type() with @lru_cache since it's too slow to be called for every
+    # QuerySet evaluation.
+    def __reduce__(self):
+        return unpickle_named_row, (names, tuple(self))
+
+    return type(
+        "Row",
+        (namedtuple("Row", names),),
+        {"__reduce__": __reduce__, "__slots__": ()},
+    )
+
+
+class AltersData:
+    """
+    Make subclasses preserve the alters_data attribute on overridden methods.
+    """
+
+    def __init_subclass__(cls, **kwargs):
+        for fn_name, fn in vars(cls).items():
+            if callable(fn) and not hasattr(fn, "alters_data"):
+                for base in cls.__bases__:
+                    if base_fn := getattr(base, fn_name, None):
+                        if hasattr(base_fn, "alters_data"):
+                            fn.alters_data = base_fn.alters_data
+                        break
+
+        super().__init_subclass__(**kwargs)