You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: plotcities.m
    path of file: ./repos/Algorithms_MathModels/HeuristicAlgorithm（补分启发式算法，包括神经网络、模拟退火、遗传算法）/模拟退火算法/TSP(SA)
    
    the code of the file until where you have to start completion: function h = plotcities(province, border, city)
% PLOTCITIES

    
function h = plotcities(province, border, city)
% PLOTCITIES
% h = PLOTCITIES(province, border, city) draw the map of China, and return 
% the route handle.

global h;
% draw the map of China
plot(province.long, province.lat, 'color', [0.7,0.7,0.7])
hold on
plot(border.long  , border.lat  , 'color', [0.5,0.5,0.5], 'linewidth', 1.5);
 

% plot a NaN route, and global the handle h.
h = plot(NaN, NaN, 'b-', 'linewidth', 1);

% plot cities as green dots
plot([city(2:end