list doubt.

Question

Hello teacher,
I tried a code for the below problem statement.
(Write a program that accepts a comma-separated sequence of words as input and prints the words in a comma-separated sequence after sorting them alphabetically.)
My code is below .But I got None as output.
code:
words=input("Enten words:")
a=words.split(",")
b=a.sort()
print(b)
But again I wrote the code as below. And I got an answer.
words=input("Enten words:")
a=words.split(",")
a.sort()
print(a)
so could you please tell me what is difference between these codes? And why it does not give me the output in 1st program.

Answer 1

sort in an inplace sort.it returns None.So b is None and a is sorted.
in opposit sorted(a) returns a new list.
a.sort()
print(a)