Cleaning messy list with a function - everything works except for the last step, help please!

Hi all, I tried to create a function that would clean any messy lists for non integers. My function works until the last item in the loop. I hope you can see my code in lists.py (please tell me otherwise how I can attach my code to this question), and here below is the result from the console at each step:

[1, 'a', 2, 3, False, [1,2,3], [1,3,2], True] #that's my print(messy_list)

['a', False, [1,2,3], [1,3,2], True] #that's my blist, or the list of non-integers to remove

[1, 2, 3,False, [1,2,3], [1,3,2], True] #first iteration of my for loop -> removed the 'a', hurray

[1, 2, 3, [1,2,3], [1,3,2], True] #second iteration of my for loop -> removed the False, hurray

[1, 2, 3, [1,3,2], True] #third iteration of my for loop -> removed the [1,2,3] list, hurray

[1, 2, 3, True] #fourth iteration of my for loop -> removed the True, hurray

[2, 3, True] #fifth iteration of my for loop and last -> WHAT HAPPENED? Why did it remove my 1 and not the True?

messy_list = ["a", 2, 3, 1, False, [1, 2, 3]]

# Your code goes below here
messy_list.insert(0,messy_list.pop(3))

def isboolean(item):
    if type(item) in (float,int):
        return item
    else:
        None

def remove_notint(alist):
    blist = []
    for item in alist:
        try:
            int(isboolean(item))
        except TypeError:
            blist.append(item)

    for item in blist:    
        try:
            alist.remove(item)
            print(alist)
        except ValueError:
            pass

    return alist


print(messy_list)
remove_notint(messy_list)