Remove DefaultOrderedDict (dicts are ordered now)

pytensor/graph/rewriting/db.py

 import copy
 import math
 import sys
+from collections import defaultdict
 from collections.abc import Iterable, Sequence
 from functools import cmp_to_key
 from io import StringIO
@@ -9,7 +10,6 @@ from typing import Union
 from pytensor.configdefaults import config
 from pytensor.graph.rewriting import basic as pytensor_rewriting
 from pytensor.misc.ordered_set import OrderedSet
-from pytensor.utils import DefaultOrderedDict
 
 
 RewritesType = pytensor_rewriting.GraphRewriter | pytensor_rewriting.NodeRewriter
@@ -23,7 +23,7 @@ class RewriteDatabase:
     """
 
     def __init__(self):
-        self.__db__ = DefaultOrderedDict(OrderedSet)
+        self.__db__ = defaultdict(OrderedSet)
         self._names = set()
         # This will be reset by `self.register` (via `obj.name` by the thing
         # doing the registering)

pytensor/utils.py

@@ -6,15 +6,12 @@ import os
 import struct
 import subprocess
 import sys
-from collections import OrderedDict
-from collections.abc import Callable
 from functools import partial
 
 
 __all__ = [
     "get_unbound_function",
     "maybe_add_to_os_environ_pathlist",
-    "DefaultOrderedDict",
     "subprocess_Popen",
     "call_subprocess_Popen",
     "output_subprocess_Popen",
@@ -376,36 +373,3 @@ class Singleton:
 
     def __hash__(self):
         return hash(type(self))
-
-
-class DefaultOrderedDict(OrderedDict):
-    def __init__(self, default_factory=None, *a, **kw):
-        if default_factory is not None and not isinstance(default_factory, Callable):
-            raise TypeError("first argument must be callable")
-        OrderedDict.__init__(self, *a, **kw)
-        self.default_factory = default_factory
-
-    def __getitem__(self, key):
-        try:
-            return OrderedDict.__getitem__(self, key)
-        except KeyError:
-            return self.__missing__(key)
-
-    def __missing__(self, key):
-        if self.default_factory is None:
-            raise KeyError(key)
-        self[key] = value = self.default_factory()
-        return value
-
-    def __reduce__(self):
-        if self.default_factory is None:
-            args = tuple()
-        else:
-            args = (self.default_factory,)
-        return type(self), args, None, None, iter(self.items())
-
-    def copy(self):
-        return self.__copy__()
-
-    def __copy__(self):
-        return type(self)(self.default_factory, self)