3)Could you please help me to solve this problem? (ONLY WITH PYTHON PROGRAMMING LANGUAGE)

Assume s is a string of lower case characters. Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, if s = 'azcbobobegghak1', then your program should print Longest substring in alphabetical order is: baggy In the case of ties, print the first substring. For example, if s= 'abcbcd', then your program should print Longest substring in alphabetical order is: abc