        def generic_visit(self, node):
            if type(node) not in SAFE_NODES:
                #raise Exception("invalid expression (%s) type=%s" % (expr, type(node)))
                raise Exception("invalid expression (%s)" % expr)
            super(CleansingNodeVisitor, self).generic_visit(node)
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.