Compute capacities after site closures

You are given a nested dictionary redistribution where redistribution[closed_site][dest_site] equals the additional capacity required at dest_site if closed_site is shut down. The baseline capacity for each site s is baseline[s] = redistribution[s][s]. Given a set of closed sites C (possibly empty), compute and return a dictionary over the open sites O = AllSites − C with capacity[o] = baseline[o] + sum(redistribution[c][o] for c in C). Exclude closed sites from the output. For example, if C = {} return the baselines; if C = {'A'}, then capacity['B'] = baseline['B'] + redistribution['A']['B'] (e.g., 110 + 10 = 120).