Adding characters to strings

[craigmrock]

Horrible at math (and probably Python) but trying to make a function that takes a word and adds an asterisk in between the letters. Trying with a 3 letter word, but the formula should handle any size word you give it.
Here’s what I have:

word=str(input('Give me a word: '))

def starry_eyes(str):
    while word == (''):
        return ([],'*',[],'*',[])
        ```

[enceladus]

word = 'python'
print('*'.join(word))