I can define and eval BNF definitions

evaluators/PythonEvaluator.py

@@ -15,6 +15,10 @@ log = logging.getLogger(__name__)
 class PythonEvaluator(OneReturnValueEvaluator):
     NAME = "Python"
 
+    """
+    Evaluate a Python node, ie, evaluate some Python code
+    """
+
     def __init__(self):
         super().__init__(self.NAME, 50)