diff --git a/qtconsole/util.py b/qtconsole/util.py
index 90f2c677..0c266451 100644
--- a/qtconsole/util.py
+++ b/qtconsole/util.py
@@ -204,7 +204,7 @@ def compute_item_matrix(items, empty=None, *, separator_size=2, displaywidth=80)
     )
 
 
-def columnize(items):
+def columnize(items, separator="  ", displaywidth=80):
     """Transform a list of strings into a single string with columns.
 
     Parameters
@@ -216,8 +216,6 @@ def columnize(items):
     -------
     The formatted string.
     """
-    separator = "  "
-    displaywidth = 80
     if not items:
         return "\n"
     matrix, info = compute_item_matrix(