statistic: fixing initalisation of raw_data

src/pipedream/utils/statistics.py

@@ -49,7 +49,7 @@ class Statistics(yaml.YAML_Struct):
                histogram: ty.Sequence[float] = None,
                raw_data: ty.List[float] = None,
                ):
-    self.raw_data    = raw_data or []
+    self.raw_data    = raw_data if raw_data is not None else []
     self.num_samples = float(num_samples)
     self.mean        = float(mean)
     self.stddev      = float(stddev)