attempt at an insertion sort

inplace_insertion_sort.py

def inplace_insertion_sort(unsorted_list, split_index=None):
    # if we have no split_index yet we know this is first iteration so lets split it
    split_index = 1 if not split_index else split_index
    # loop over each item in unsorted list
    for uitem in unsorted_list[split_index:len(unsorted_list)]:
        # reverse the sorted list to loop over as we compare right to left
        for index, sitem in enumerate(reversed(unsorted_list[:split_index])):
            if uitem > sitem:
                # remove from unsorted so we don't look at it again
                unsorted_list.remove(uitem)
                # insert into list
                unsorted_list.insert(len(unsorted_list[:split_index]) - index, uitem)
                # move the split point
                split_index += 1
                # get out of here
                break
        if uitem not in unsorted_list[:split_index]:
            # hey we didn't add this item it must be at beginning
            unsorted_list.remove(uitem)
            unsorted_list.insert(0, uitem)
            split_index += 1
    # return the sorted list or recursive call with what we have so far
    return unsorted_list if split_index == len(unsorted_list) else inplace_insertion_sort(unsorted_list, split_index=split_index)

if __name__ == '__main__':
    print(inplace_insertion_sort([23, 42, 4, 16, 8, 15]))

insertion_sort.py

def insertion_sort(unsorted, sorted=list()):
    # first iteration we need to start a sorted list with 1 value so we slice it off the unsorted
    if not sorted:
        sorted = unsorted[:1]
        unsorted = unsorted[1:len(unsorted)]
    # loop over each item in unsorted list, wrap with list() to copy, so we can pop from unsorted
    for uitem in list(unsorted):
        # reverse the sorted list to loop over as we compare right to left
        for index, sitem in enumerate(reversed(sorted)):
            if uitem > sitem:
                # insert to sorted list at correct position, index is opposite of what we want so subtract len()
                sorted.insert(len(sorted) - index, uitem)
                # remove from unsorted so we don't look at it again
                unsorted.remove(uitem)
                # get out of here
                break
        if uitem not in sorted:
            # hey we didn't add this item it must be at beginning
            sorted.insert(0, uitem)
            unsorted.remove(uitem)
    # return the sorted list or recursive call with what we have so far
    return sorted if len(unsorted) <= 0 else insertion_sort(unsorted, sorted)

if __name__ == '__main__':
    print(insertion_sort([23, 42, 4, 16, 8, 15]))