bus = {}

def idx2set (s):
    s = list(map(int,re.sub('(\[|\s|\])','',s).split(':')))
    if len(s)==1: return set([s[0]])
    if s[0]>s[1] : s=[s[1],s[0]]
    return set(range(s[0],s[1]+1))

print(idx2set('[1]'))
a=idx2set('[1 :7]')
b=idx2set('[ 9:7 ]')
c=a&b
print(a,b,c)
if c : print(c)
else : print('c empty')
a.update(b)
print("update:",a)
exit()