old_contents: import numpy as np
  
  
  def rotate_bbox(bbox, angle, size):
      """Rotate bounding boxes by degrees.
  
      Args:
          bbox (~numpy.ndarray): An array whose shape is :math:`(R, 4)`.
              :math:`R` is the number of bounding boxes.
          angle (float): Counter clock-wise rotation angle (degree).
              image is rotated by 90 degrees.
          size (tuple): A tuple of length 2. The height and the width
              of the image.
  
      Returns:
          ~numpy.ndarray:
          Bounding boxes rescaled according to the given :obj:`k`.
  
      """
      if angle % 90 != 0:
          raise ValueError(
              'angle which satisfies angle % 90 == 0 is only supported: {}'
              .format(angle))
          return bbox
      H, W = size
      if angle % 360 == 0:
          return bbox
  
      if angle % 360 == 90:
          rotated_bbox = np.concatenate(
              (W - bbox[:, 3:4], bbox[:, 0:1],
               W - bbox[:, 1:2], bbox[:, 2:3]), axis=1)
      elif angle % 360 == 180:
          rotated_bbox = np.concatenate(
              (H - bbox[:, 2:3], W - bbox[:, 3:4],
               H - bbox[:, 0:1], W - bbox[:, 1:2]), axis=1)
      elif angle % 360 == 270:
          rotated_bbox = np.concatenate(
              (bbox[:, 1:2], H - bbox[:, 2:3],
               bbox[:, 3:4], H - bbox[:, 0:1]), axis=1)
      rotated_bbox = rotated_bbox.astype(bbox.dtype)
      return rotated_bbox
  
new_contents: import numpy as np
  
  
  def rotate_bbox(bbox, angle, size):
      """Rotate bounding boxes by degrees.
  
      Args:
          bbox (~numpy.ndarray): An array whose shape is :math:`(R, 4)`.
              :math:`R` is the number of bounding boxes.
          angle (float): Counter clock-wise rotation angle (degree).
              image is rotated by 90 degrees.
          size (tuple): A tuple of length 2. The height and the width
              of the image.
  
      Returns:
          ~numpy.ndarray:
          Bounding boxes rescaled according to the given :obj:`k`.
  
      """
      if angle % 90 != 0:
          raise ValueError(
              'angle which satisfies angle % 90 == 0 is only supported: {}'
              .format(angle))
      H, W = size
      if angle % 360 == 0:
          return bbox
  
      if angle % 360 == 90:
          rotated_bbox = np.concatenate(
              (W - bbox[:, 3:4], bbox[:, 0:1],
               W - bbox[:, 1:2], bbox[:, 2:3]), axis=1)
      elif angle % 360 == 180:
          rotated_bbox = np.concatenate(
              (H - bbox[:, 2:3], W - bbox[:, 3:4],
               H - bbox[:, 0:1], W - bbox[:, 1:2]), axis=1)
      elif angle % 360 == 270:
          rotated_bbox = np.concatenate(
              (bbox[:, 1:2], H - bbox[:, 2:3],
               bbox[:, 3:4], H - bbox[:, 0:1]), axis=1)
      rotated_bbox = rotated_bbox.astype(bbox.dtype)
      return rotated_bbox
  
subject: remove unnecessary line in rotate_bbox