Next up was an implementation of functions such that you can do things like take f(x) and g(x) and do f+g such that (f+g)(x) == f(x) + g(x).
See the functions module literate doctest at https://github.com/jtauber/functional-differential-geometry/blob/master/functions.rst.
There is also a compose function there that I guess could be associated with an operator if I could think of a binary operator that wouldn't otherwise make sense to apply to the results of two functions.