Where did I get it wrong?!

[Tamimi1982]

I am still trying and nothing happened. What is wrong?!!!

items = 0
def omode():
    mode = input('Please enter "A" or "T" ')
    return mode
if omode().isupper() == "T":
    items = input('Please input an integer ')
while items.isdigit():
    totala = int(items)
    totala += totala
    items = input('Please input an integer ')
    if items.isdigit() == False:
        if str(items) == "q" or str(items) == "Q":
            print(totala)
        else:
            print(items,"is an invalid input")
if omode().isupper() == "A":
    items = input('Please input an integer ')
while items.isdigit():
    totala = int(items)
    totala += totala
    items = input('Please input an integer')
    if items.isdigit() == False:
        if str(items) == "q" or str(items) == "Q":
            print(totala)
        else:
            print(items,"is an invalid input")
else:
    print("This is an ivalid input")
    omode()