Exit loop by user by pressing the ENTER key

I am a python newbie and have been asked to carry out some exercises using while and for loops. I have been asked to make a program loop until exit is requested by the user hitting <Return> only. So far I have:

User = raw_input('Enter <Carriage return> only to exit: ')
running = 1
while running == 1:
    Run my program
if User == # Not sure what to put here
    Break
else
    running == 1

I have tried: (as instructed in the exercise)

if User == <Carriage return>

and also

if User == <Return>

but this only results in invalid syntax. Please could you advise me on how to do this in the simplest way possible. Thanks


I ran into this page while (no pun) looking for something else. Here is what I use:

while True:
    i = input("Enter text (or Enter to quit): ")
    if not i:
        break
    print("Your input:", i)
print("While loop has exited")