diff --git a/setup.py b/setup.py
index 0c2808e92..b7d0e8f51 100644
--- a/setup.py
+++ b/setup.py
@@ -41,6 +41,7 @@ setup(
         "Topic :: Software Development :: Build Tools",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3 :: Only"
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",