diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
index fcb7e6207e5..bb495bc1be3 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
@@ -298,7 +298,7 @@ def get_label_set(self, labels: Dict[str, str]):
         # Use simple encoding for now until encoding API is implemented
         encoded = tuple(sorted(labels.items()))
         # If LabelSet exists for this meter in memory, use existing one
-        if not encoded in self.labels:
+        if encoded not in self.labels:
             self.labels[encoded] = LabelSet(labels=labels)
         return self.labels[encoded]