It's not as powerful as what you could do with Lisp. The code is not a first-class object, so you can't for example substitute variable a for variable b. The "d

It's not as powerful as what you could do with Lisp. The code is not a first-class object, so you can't for example substitute variable a for variable b. The "data" in code as data refers to an abstract syntax tree, not just a string which happens to contain code. Python does give you access to abstract syntax trees, but because of the complexity of the language this is less useful than with Lisp.