#!/usr/bin/python3

import ast

code = 'print(1+1)'

class TestTransformer(ast.NodeTransformer):
    def visit_Num(self, node):
        return ast.copy_location(ast.Num(n=5), node)

node = ast.parse(code)
exec(compile(node, '<ast>', mode='exec'))

# Change numbers to 5
node = TestTransformer().visit(node)
exec(compile(node, '<ast>', mode='exec'))