Importations

[s-mishra]

We should have some mechanism to do importations in the model. Right now we have a fixed scheme which we can take an input argument in future.

This is a requirement down the line

[agandy]

we could use a setup similar to how we specify the "observations" :
a list of importation mechanisms as an additional argument - (usually there would be one, but we could have multiple active as well - eg for importation between countries and for importation from "the rest of the world".