Fix lint

Author: kozikkamil

labelbox/data/mixins.py

@@ -55,6 +55,9 @@ class CustomMetricsMixin(BaseModel):
     def dict(self, *args, **kwargs):
         res = super().dict(*args, **kwargs)
 
+        if "customMetrics" in res and res["customMetrics"] is None:
+            res.pop("customMetrics")
+
         if "custom_metrics" in res and res["custom_metrics"] is None:
             res.pop("custom_metrics")