class_docstr: This method returns a copy of this image, rotated the given
  number of degrees counter clockwise around its center.
code: def create_rotation_matrix(self, offset=0):
      center = (self.center[0] + offset, self.center[1] + offset)
      rm = cv2.getRotationMatrix2D(tuple(center), self.angle, 1)
      if self.expand:
          # Find the coordinates of the center of rotation in the new image
          # The only point for which we know the future coordinates is the center of the image
          rot_im_center = cv2.transform(
              self.image_center[None, None, :] + offset, rm
          )[0, 0, :]
          new_center = (
              np.array([self.bound_w / 2, self.bound_h / 2])
              + offset
              - rot_im_center
          )
          # shift the rotation center to the new coordinates
          rm[:, 2] += new_center
      return rm
  
imports: import numpy
  import torch
  import torch.nn.functional
  from fvcore.transforms.transform import CropTransform, HFlipTransform, NoOpTransform, Transform, TransformList
  from PIL import Image
label_desc: Use image node_id 5 for calling the RotationTransform obj's underlying member method code with example usage: obj.create_rotation_matrix(offset) and returns: rm