diff --git a/dipy/workflows/multi_io.py b/dipy/workflows/multi_io.py
index eca1aa5d99..12e5d6c391 100644
--- a/dipy/workflows/multi_io.py
+++ b/dipy/workflows/multi_io.py
@@ -175,9 +175,18 @@ def io_iterator_(frame, fnc, output_strategy="absolute", mix_names=False):
         Properly instantiated IOIterator object.
 
     """
+
+    # Create a new object that does not contain the ``self`` dict item
+    def _selfless_dict(_values):
+        return {key: val for key, val in _values.items() if key != "self"}
+
     args, _, _, values = inspect.getargvalues(frame)
     args.remove("self")
-    del values["self"]
+    # Create a new object that does not contain the ``self`` dict item from the
+    # provided copy of the local symbol table returned by ``getargvalues``.
+    # Avoids attempting to remove it from the object returned by
+    # ``getargvalues``.
+    values = _selfless_dict(values)
 
     spargs, defaults = get_args_default(fnc)