diff --git a/tl_cpu.py b/tl_cpu.py
index c186e350..54c5c1f0 100644
--- a/tl_cpu.py
+++ b/tl_cpu.py
@@ -206,7 +206,7 @@ def __init__(self, known_cpus=(), nocheck=False, env=Env()):
             newcounters = { "cpu": 4 }
         else:
             newcounters = { "cpu": 8 }
-        if self.counters is None:
+        if not self.counters:
             self.counters = newcounters
         if not nocheck and not self.env.forcecounters:
             for j in ("cpu", "cpu_core", "cpu_atom"):