Apart from chaining generators, you can write a simple helper to pipe general expressions.

    def pipe(cur_val, *fns):
        """
        Pipes `cur_val` through `fns`.
        ::
            def sqr(x): return x * x

            def negate(x): return -x

        `pipe(5, sqr, negate)`

        is the same as
        ::
            negate(sqr(5))
        """
        for fn in fns:
            cur_val = fn(cur_val)
        return cur_val

I find `pipe(5, sqr, negate)` neater than `negate(sqr(5))`, especially when the nesting is greater than 2.

This is inspired by clojure's threading macro -> and a re-factoring of @fogus's code snippet on stack overflow. He used reduce to implement the loop - though loops can be implemented with reduce, and that's how you generally do it in clojure et al., it isn't idiomatic Python.