here is a better solution using regex:
import re
def exiSt(short,long):
r = ''.join(["(.*"+str[x]+")" for x in short])
return re.match(r,','.join([str(x) for x in long])) == None
long = [1, 2, 3, 4, 5]
short1 = [1,2,5]
short2 = [1,5,3]
exiSt(short1,long)
>> True
exiSt(short2,long)
>> False