What a difference print() makes

[DeaD_EyE]

As a side note, you could iterate over the enumerate(list1) and then you get (index, list_element).

list1 = ["cat", "dog", "cat", "dog"]


def get_all_indicies(iterable, item):
    for index, elemnt in enumerate(iterable):
        if item == elemnt:
            yield index


all_indicies = list(get_all_indicies(list1, "cat"))

Otherwise, you can use list1.index("item_to_find", START_INDEX).

list1 = ["cat", "dog", "cat", "dog"]


def get_all_indicies(list_like, item):
    index = 0

    while True:
        try:
            index = list_like.index(item, index)
            yield index
        except ValueError:
            return

        index += 1


list(get_all_indicies(list1, "cat"))