Amend weight description

abstract_syntax_tree.py

@@ -28,7 +28,7 @@ class OperatorNode:
     def __init__(self, operator, children):
         self.operator = operator  # operator object (e.g., Add, Subtract, etc.)
         self.children = children  # list of children nodes (operands)
-        self.weight = operator.weight + sum([child.weight for child in children])  # weight of the node
+        self.weight = operator.weight + sum([child.weight for child in children])  # weight of the program
         self.type = operator.return_type  # return type of the operator object
 
     def evaluate(self, input = None):