Why do I get double spaces if the user has no middle name

Question

I'm trying to learn Python and this is my first script so please be patient with me :)

I ask the player for first_name, last_name and if they have a middle_name, if they do that is stored, if not it is None.

When they have a middle name there is a single space between first middle and last names. But, if they do not have a middle name I get first then two spaces then last. It's not a significant issue but it's bugging me and I want to understand why it is happening.

Here's my code so far:

first_name = input("What is your first name? ")
last_name = input("What is your last name? ")
while True:
    middle = input("Do you have a middle name? (y/n) ")
    if middle.upper() not in ("Y", "N"):
        print("whats does {} mean? You were meant to type 'y' or 'n'! Try again.." .format(middle))
    elif middle.upper() == "Y":
        middle_name = input("What is it? ")
        break
    elif middle.upper() == "N":
        middle_name = None
        break

# is_middle_empty = bool(middle_name)
# print(is_middle_empty)
print("So your full name is {} {} {}? ".format(first_name, '' if middle_name is None else middle_name, last_name))
import time
time.sleep(1)
print("Hmmm..")
time.sleep(1)
just_first = str(input("Should I just call you {}? (y/n) ".format(first_name)))
if just_first.upper() == "Y":
   player = first_name
   print("Great, nice to meet you", player)
elif just_first.upper() != "Y":
   name = first_name, "" if middle_name is None else middle_name, last_name
   player = " ".join(name)
   print("Sorry about that, let's stick to {} then." .format(player))
print()
adventure = input("So do you fancy a quick adventure? (y/n) ")
if adventure.upper() == "Y":
    print("Great then lets set off...")
elif adventure.upper() == "N":
    print("Ah well, I guess we can't all be ubercool adventurers like me, fairwell {}, I hope we meet again some day." .format(player))