diff --git a/optimus/dataframe/rows.py b/optimus/dataframe/rows.py
index 08a34160..06f0587e 100644
--- a/optimus/dataframe/rows.py
+++ b/optimus/dataframe/rows.py
@@ -186,7 +186,7 @@ def between(columns, lower_bound=None, upper_bound=None, invert=False, equal=Fal
         # TODO: should process string or dates
         columns = parse_columns(self, columns, filter_by_column_dtypes=PYSPARK_NUMERIC_TYPES)
         if bounds is None:
-            bounds = (lower_bound, upper_bound)
+            bounds = [(lower_bound, upper_bound)]
 
         def _between(_col_name):