diff --git a/quantus/metrics/randomisation/smooth_mprt.py b/quantus/metrics/randomisation/smooth_mprt.py
index b5294575..a0f308b4 100644
--- a/quantus/metrics/randomisation/smooth_mprt.py
+++ b/quantus/metrics/randomisation/smooth_mprt.py
@@ -6,6 +6,7 @@
 # You should have received a copy of the GNU Lesser General Public License along with Quantus. If not, see <https://www.gnu.org/licenses/>.
 # Quantus project URL: <https://github.com/understandable-machine-intelligence-lab/Quantus>.
 
+import sys
 import warnings
 from typing import (
     Any,