advanced drought related indices

The indices SPI and SPEI are included in the ET-SCI list, but has so far been beyond the horizon. However I just saw a python implementation that seems to be solid enough in terms of institutional support and interesting for their approach towards large data efficiency. @a002160 have a look at some point -- something we could benefit from hooking up to? The other indices on their list are well established and widely used, but typically not considered as "indices in sense where we are coming from".