how to make all letters lowercase in python code example

Example 1: how to check if a letter is lowercase in python

for c in s:
    if c.islower():
         print c

Example 2: python lowercase

// turn to lower/upper
string = string.upper()
string = string.lower()

// check if all letter are lower or upper
string.islower()
string.isupper()

Example 3: how do you change a string to only uppercase in python

original = Hello, World!

#both of these work
upper = original.upper()
upper = upper(original)