add_cmt
Add a CMT column to the model dataset and datainfo if not existed
In case of multiple doses, this method is dependent on the presence of an admid column to correctly number each dose.
NOTE : Existing CMT is based on datainfo type being set to 'compartment' and a column named 'CMT' can be replaced
add_cmt(model)
model
: (Model) Pharmpy model(model : Model) Pharmpy model
get_admid : Get or create an admid column
get_cmt : Get or create a cmt column