Christmas Tree (idk really lol)

christmasTree.py

def branch(num : int, f : int):
    return f'{" " * f}{"*" * num}*{"*" * num}'

def christmas(f):
    e = None
    for i in range(f):
        print(branch(i,f-i))
        if e is None:
            e = branch(i+1, f-i-1)
    print(e, e, sep='\n')

number = int(input("Size: "))
christmas(number)

# example output:
# Size: 11
#            *
#           ***
#          *****
#         *******
#        *********
#       ***********
#      *************
#     ***************
#    *****************
#   *******************
#  *********************
#           ***
#           ***