--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jb2_GFF/_utils.py	Sun Jan 28 06:48:52 2024 +0000
@@ -0,0 +1,49 @@
+class defaultdict(dict):
+    """Back compatible defaultdict:
+    http://code.activestate.com/recipes/523034/"""
+
+    def __init__(self, default_factory=None, *a, **kw):
+        if default_factory is not None and not hasattr(
+            default_factory, "__call__"
+        ):
+            raise TypeError("first argument must be callable")
+        dict.__init__(self, *a, **kw)
+        self.default_factory = default_factory
+
+    def __getitem__(self, key):
+        try:
+            return dict.__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, self.items()
+
+    def copy(self):
+        return self.__copy__()
+
+    def __copy__(self):
+        return type(self)(self.default_factory, self)
+
+    def __deepcopy__(self, memo):
+        import copy
+
+        return type(self)(
+            self.default_factory, copy.deepcopy(self.items())
+        )
+
+    def __repr__(self):
+        return "defaultdict(%s, %s)" % (
+            self.default_factory,
+            dict.__repr__(self),
+        )