chore(flake8): if observer is not None

Author: TomMonks

output_analysis.py

@@ -77,7 +77,7 @@ def __init__(
         self._sq = None
         self.alpha = alpha
         self._observers = []
-        if not observer is None:
+        if observer is not None:
             self.register_observer(observer)
 
         if isinstance(data, np.ndarray):