diff --git a/quapy/method/__init__.py b/quapy/method/__init__.py
index 8a30451..01c19bc 100644
--- a/quapy/method/__init__.py
+++ b/quapy/method/__init__.py
@@ -20,6 +20,7 @@ AGGREGATIVE_METHODS = {
     aggregative.EMQ,
     aggregative.HDy,
     aggregative.DyS,
+    aggregative.SMM,
     aggregative.X,
     aggregative.T50,
     aggregative.MAX,
diff --git a/quapy/method/aggregative.py b/quapy/method/aggregative.py
index a2e03ae..7ab73fb 100644
--- a/quapy/method/aggregative.py
+++ b/quapy/method/aggregative.py
@@ -1,6 +1,5 @@
 from abc import abstractmethod
 from copy import deepcopy
-import string
 from typing import Callable, Union
 import numpy as np
 from joblib import Parallel, delayed