def space_list(line: str) -> list:
    """"Given a string, return a list of index positions where a blank space occurs.
    >>> space_list("    abc ")
    [0, 1, 2, 3, 7]
    """
    spaces = []
    for idx, car in enumerate(list(line)):
        if car == " ":
            spaces.append(idx)
    return spaces