How to execute a function inside a python script?

How can I execute the below simple script called foo.py from the (bash) command line?

def hello():
    return 'Hi :)'

I tried the following and got an error.

 $ python -c 'import foo; print foo.hello()'

  File "<string>", line 1
    import foo; print foo.hello()
                      ^
SyntaxError: invalid syntax

I’m able to execute the following but just receive no output.

$ python foo.py
$

>Solution :

print foo.hello()

Is this Python2?

remove that print before function call:

$ python -c 'import foo; foo.hello()'

Or make it like python3 syntax:

$ python -c 'import foo; print(foo.hello())'