diff --git a/quapy/plot.py b/quapy/plot.py
index cdc3bd5..78911ec 100644
--- a/quapy/plot.py
+++ b/quapy/plot.py
@@ -1,6 +1,6 @@
 from collections import defaultdict
 import matplotlib.pyplot as plt
-from matplotlib.cm import get_cmap
+from matplotlib.pyplot import get_cmap
 import numpy as np
 from matplotlib import cm
 from scipy.stats import ttest_ind_from_stats
diff --git a/setup.py b/setup.py
index 6e0f394..d0f299a 100644
--- a/setup.py
+++ b/setup.py
@@ -113,7 +113,7 @@ setup(
 
     python_requires='>=3.8, <4',
 
-    install_requires=['scikit-learn', 'pandas', 'tqdm', 'matplotlib', 'joblib', 'xlrd', 'abstention', 'ucimlrepo'],
+    install_requires=['scikit-learn', 'pandas', 'tqdm', 'matplotlib', 'joblib', 'xlrd', 'abstention', 'ucimlrepo', 'certifi'],
 
     # List additional groups of dependencies here (e.g. development
     # dependencies). Users will be able to install these using the "extras"