Coursera python for everybody 5.2 assignment

[SteppentigerV2]

I'm stuck with this. This is the requirement 5.2 Write a program that repeatedly prompts a user for integer numbers until the user enters 'done'. Once 'done' is entered, print out the largest and smallest of the numbers. If the user enters anything other than a valid number catch it with a try/except and put out an appropriate message and ignore the number. Enter 7, 2, bob, 10, and 4 and match the output below.

My code:

largest = None
smallest = None
while True:
    num = float(input("Enter a number: "))
    for i in num:
     if i > largest:
     largest = i
    print(largest)
    break
    for i in num:
    if num <smallest
    smallest=num
    print(num)
    except
    print("Invalid input)
    if num == "done" : break
    print(num)

print("Maximum is", largest, "Minimum is", smallest)