Efficient fixed-base modular exponentiation with powmod_exp_list?

[danrr]

The experimental powmod_exp_list function that was added recently appears to loop over the exponent argument and call mpz_powm internally.

The similar powmod_base_list makes sense to be implemented like this and to allow threaded parallelism for quicker computation. On the other hand, modular exponentiation with the same base can be made more efficient (in terms of overall computation) by sharing partial results or doing some pre-computation of set exponents.

Is this something that is coming down the line?

Would integrating something like verificatum/verificatum-gmpmee for this usecase be in the scope of gmpy?