diff --git a/.arclint b/.arclint
--- a/.arclint
+++ b/.arclint
@@ -16,6 +16,13 @@
             "type": "autopep8",
             "include": "(\\.py$)"
         },
+        "flake8": {
+            "type": "flake8",
+            "include": "(\\.py$)",
+            "flags": [
+                "--select=F401"
+            ]
+        },
         "lint-format-strings": {
             "type": "script-and-regex",
             "include": "(^src/.*\\.(h|c|cpp)$)",
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -124,12 +124,12 @@
 6. Code formatting tools
 
 If code formatting tools do not install automatically on your system, you
-may have to install clang-format-7 and autopep8. clang-format-7 can be installed
-from https://releases.llvm.org/download.html or https://apt.llvm.org
+may have to install clang-format-7, autopep8 and flake8. clang-format-7 can be
+installed from https://releases.llvm.org/download.html or https://apt.llvm.org
 
-To install autopep8 on Ubuntu:
+To install autopep8 and flake8 on Ubuntu:
 ```
-sudo apt-get install python-autopep8
+sudo apt-get install python-autopep8 flake8
 ```