code: def get_portfolios3():
      
      g1 = [0]
      g2 = [1]
      g7 = [2]
      g13 = [3]
      g14 = [4] # sync cond
      g15 = [5]
      g16 = [6]
      g18 = [7]
      g21 = [8]
      g22 = [9]
      g23 = [10, 11]
  
      portfolios = [g1 + g15 + g18,
                    g2 + g16 + g21,
                    g13 + g22,
                    g7 + g23]
  
      passive = g14 # sync_cond
  
      return portfolios, passive
docs: Returns portfolios with U12 and U20 generators removed and generators
      of the same type at the same bus aggregated.