country_fuel_summary = gppd
.groupby("country_long", "primary_fuel")
.rollup({
total_capacity_mw: (d) => op.sum(d.capacity_mw),
count: op.count()
})
.groupby("country_long")
.derive({
proportion_of_country_capacity: (d) =>
d.total_capacity_mw / op.sum(d.total_capacity_mw)
})
.orderby(aq.desc("total_capacity_mw"))