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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 _unwrap_one_layer(r, L, n):
 """For a set of points in a 2 dimensional periodic system, extend the set of points to tile the points at a given period. Parameters r: float array, shape (:, 2). Set of points. L: float array, shape (2,) System lengths. n: integer. Period to unwrap. Returns ------- rcu: float array, shape (:, 2). The set of points. tiled at the periods at a distance `n` from the origin. """

    try:
        L[0]
    except (TypeError, IndexError):
        L = np.ones([r.shape[1]]) * L
    if n == 0:
        return list(r)
    rcu = []
    for x, y in r:
        for ix in range(-n, n + 1):
            for iy in range(-n, n + 1):
                if abs(ix) == n or abs(iy) == n:
                    rcu.append(np.array([x + ix * L[0], y + iy * L[1]]))
    return rcu