diff --git a/test_libs/pyspec/setup.py b/test_libs/pyspec/setup.py
index 3856640ab..fe14c498c 100644
--- a/test_libs/pyspec/setup.py
+++ b/test_libs/pyspec/setup.py
@@ -10,6 +10,7 @@ setup(
         "pycryptodome==3.7.3",
         "py_ecc>=1.6.0",
         "typing_inspect==0.4.0",
-        "ssz==0.1.0a10"
+        "ssz==0.1.0a10",
+        "dataclasses==0.6",
     ]
 )