Check whether a string starts and ends with the same character or not (using Regular Expression)

import re

regex = r'^[a-z]$|^([a-z]).*\1$'

def check(string):

if(re.search(regex, string)):

print("Valid")

else:

print("Invalid")

if __name__ == '__main__' :

sample1 = "abba"

sample2 = "a"

sample3 = "abcd"

check(sample1)

check(sample2)

check(sample3)