Vigenere cipher rules

Question

I am working on a vigenere cipher in python (which works perfectly).
And I was asking what is the supposed behavior when in the key there is a space. It is equivalent to an a ? It don't change the message letter ?

Answer 1

Sure, I gonna do my own alphabet !
Thank you again for responding so quickly ;)

Answer 2

I think the "correct" way to deal with space is to don't use them, but common, it's not funny 😂

Answer 3

Thank you very much, but is there any "official" rule for vigenre which say what to do with the space ?
And you, what do you think I should do with space?