Get regions for each process
Value
a list of named vectors, where each vector contains the regions
associated with a process. The names of the list elements are the process
names, and the values are the regions associated with each process.
If return_list
is FALSE, the function returns a data frame with two
columns: "process" and "region", where each row represents a process-region
pair. The data frame is unique and sorted by process and region.