Chaining classmethod and property no longer supported in Python 3.13

Author: ricardoV94

pymc/distributions/distribution.py

@@ -192,20 +192,19 @@ def support_point(op, rv, *dist_params):
         return new_cls
 
 
-class _class_or_instancemethod(classmethod):
-    """Allow a method to be called both as a classmethod and an instancemethod.
+class _class_or_instance_property(property):
+    """Allow a property to be accessed from a class or an instance.
 
-    Priority is given to the instancemethod.
+    Priority is given to the instance.
 
     This is used to allow extracting information from the signature of a SymbolicRandomVariable
-    which may be provided either as a class attribute or as an instance attribute.
+    which may be available early as a class attribute or only later as an instance attribute.
 
-    Adapted from https://stackoverflow.com/a/28238047
+    Adapted from https://stackoverflow.com/a/13624858
     """
 
-    def __get__(self, instance, type_):
-        descr_get = super().__get__ if instance is None else self.__func__.__get__
-        return descr_get(instance, type_)
+    def __get__(self, owner_self, owner_cls):
+        return self.fget(owner_self if owner_self is not None else owner_cls)
 
 
 class SymbolicRandomVariable(MeasurableOp, OpFromGraph):
@@ -241,8 +240,7 @@ class SymbolicRandomVariable(MeasurableOp, OpFromGraph):
     _print_name: tuple[str, str] = ("Unknown", "\\operatorname{Unknown}")
     """Tuple of (name, latex name) used for for pretty-printing variables of this type"""
 
-    @_class_or_instancemethod
-    @property
+    @_class_or_instance_property
     def signature(cls_or_self) -> None | str:
         # Convert "expanded" signature into "vanilla" signature that has no rng and size tokens
         extended_signature = cls_or_self.extended_signature
@@ -257,40 +255,28 @@ def signature(cls_or_self) -> None | str:
 
         return signature
 
-    @_class_or_instancemethod
-    @property
+    @_class_or_instance_property
     def ndims_params(cls_or_self) -> Sequence[int] | None:
-        """Number of core dimensions of the distribution's parameters."""
+        """Return number of core dimensions of the distribution's parameters."""
         signature = cls_or_self.signature
         if signature is None:
             return None
         inputs_signature, _ = _parse_gufunc_signature(signature)
         return [len(sig) for sig in inputs_signature]
 
-    @_class_or_instancemethod
-    @property
+    @_class_or_instance_property
     def ndim_supp(cls_or_self) -> int | None:
-        """Number of support dimensions of the RandomVariable.
+        """Return number of support dimensions of the RandomVariable.
 
         (0 for scalar, 1 for vector, ...)
         """
         signature = cls_or_self.signature
         if signature is None:
-            return None
+            return getattr(cls_or_self, "_ndim_supp", None)
         _, outputs_params_signature = _parse_gufunc_signature(signature)
         return max(len(out_sig) for out_sig in outputs_params_signature)
 
-    @_class_or_instancemethod
-    def _parse_extended_signature(cls_or_self) -> tuple[tuple[str, ...], tuple[str, ...]] | None:
-        extended_signature = cls_or_self.extended_signature
-        if extended_signature is None:
-            return None
-
-        fake_signature = extended_signature.replace("[rng]", "(rng)").replace("[size]", "(size)")
-        return _parse_gufunc_signature(fake_signature)
-
-    @_class_or_instancemethod
-    @property
+    @_class_or_instance_property
     def default_output(cls_or_self) -> int | None:
         extended_signature = cls_or_self.extended_signature
         if extended_signature is None:
@@ -374,7 +360,7 @@ def __init__(
         if "ndim_supp" in kwargs:
             # For backwards compatibility we allow passing ndim_supp without signature
             # This is the only variable that PyMC absolutely needs to work with SymbolicRandomVariables
-            self.ndim_supp = kwargs.pop("ndim_supp")
+            self._ndim_supp = kwargs.pop("ndim_supp")
 
         if self.ndim_supp is None:
             raise ValueError("ndim_supp or signature must be provided")