Function .join()

Question

def digit_sum(x):
emp = ["2"]
y = str(x)
emp.append(y)
"x".join(emp)
print (emp)

digit_sum(1234)

output:

['2', '1234']

Why is the function .join() not working? Is it because i place the .join() in the function?
Thanks in advance!

Answer 1

.join returns a string but you have to assign to something. For the time being replace the last print command with print("x".join(emp))

Answer 2

Oh now i understand! Thanks for you help!