select stellar phases for a composite population

[saharsh1]

The select phase method of an ssp be inherited by a composite population?

For example, following the tutorial example of combining young, intermediate and old populations, we do something like csp = ssp_old + ssp_intermediate + ssp_young

Then, is there an option to select the phases directly on the resulting population, rather than going back to the single ones and combining them again? For example:

# generate boolean phase masks
MS  = csp.select_phase('MS')
RGB = csp.select_phase('RGB')
AGB = csp.select_phase('AGB')