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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 arr_to_vector(arr):
 """Reshape a multidimensional array to a vector. """

    dim = array_dim(arr)
    tmp_arr = []
    for n in range(len(dim) - 1):
        for inner in arr:
            for i in inner:
                tmp_arr.append(i)
        arr = tmp_arr
        tmp_arr = []
    return arr