code: def affine_horizontal_flip_matrix(prob=0.5):
      
      factor = np.random.uniform(0, 1)
      if prob >= factor:
          filp_matrix = np.array([[ -1. , 0., 0. ], \
                [ 0., 1., 0. ], \
                [ 0., 0., 1. ]])
          return filp_matrix
      else:
          filp_matrix = np.array([[ 1. , 0., 0. ], \
                [ 0., 1., 0. ], \
                [ 0., 0., 1. ]])
          return filp_matrix
docs: Create an affine transformation matrix for image horizontal flipping.
      NOTE: In OpenCV, x is width and y is height.
  
      Parameters
      ----------
      prob : float
          Probability to flip the image. 1.0 means always flip.
  
      Returns
      -------
      numpy.array
          An affine transform matrix.