def get_index_of_max(iterable):
    """
    Return the first index of one of the maximum items in the iterable.
    """
    max_i = -1
    max_v = float('-inf')

    for i, iter in enumerate(iterable):
        temp = max_v
        max_v = max(iter,max_v)
        if max_v != temp:
            max_i = i

    return max_i