diff --git a/docs/requirements.txt b/docs/requirements.txt
index 5e34d75cf3..28cfa53799 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,9 +1,8 @@
 sphinx
 sphinx_rtd_theme
-numpy>=1.7
 contextlib2
-cloudpickle>=0.3.1
 graphviz>=0.8
+numpy>=1.7
 observations>=0.1.4
 opt_einsum>=2.3.2
-tqdm>=4.25
+tqdm>=4.28
diff --git a/setup.py b/setup.py
index 09fc7343dc..3f2c1f31ad 100644
--- a/setup.py
+++ b/setup.py
@@ -83,6 +83,7 @@
         # add them to `docs/requirements.txt`
         'contextlib2',
         'graphviz>=0.8',
+        # numpy is necessary for some functionality of PyTorch
         'numpy>=1.7',
         'opt_einsum>=2.3.2',
         'six>=1.10.0',