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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def space_list(line: str) -> List[int]: """ Given a string, return a list of index positions where a blank space occurs. :param line: :return: [0, 1, 2, 3, 7] """

    spaces = []
    for idx, car in enumerate(list(line)):
        if car == " ":
            spaces.append(idx)
    return spaces