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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 ioa(boxes1, boxes2):
 """Computes pairwise intersection-over-area between box collections. Intersection-over-area (ioa) between two boxes box1 and box2 is defined as their intersection area over box2's area. Note that ioa is not symmetric, that is, IOA(box1, box2) != IOA(box2, box1). Args: boxes1: a numpy array with shape [N, 4] holding N boxes. boxes2: a numpy array with shape [M, 4] holding N boxes. Returns: a numpy array with shape [N, M] representing pairwise ioa scores. """

  intersect = intersection(boxes1, boxes2)
  inv_areas = np.expand_dims(1.0 / area(boxes2), axis=0)
  return intersect * inv_areas