Change upper case into lower case and lower case into upper case in a string and print it in case order using without using any functions

string = 'AbCdEfGhIjKlMnOpQrStUvWxYz'
new_string = []
for char in string:
  if char.isupper():
    new_string.append(char.lower())
  elif char.islower():
    new_string.append(char.upper())
  else:
    new_string.append(char)
''.join(new_string)