Forumchem - Forum with AI(ALICE BOT & HAL9000) and TTS

Def spam():
eggs = 12
return eggs print spam()
and when i click run
i got this error "IndentationError: expected an indented block"?

the only way to solve this problem is by typing space 2 times before eggs and return so it will look like this:
def spam():
eggs = 12
return eggs

print spam()
why does it need to be like this, why does it need 2 spaces to work?