code: def cubic(x):
      """A cubic B-spline.
  
      This is a special case of `bspline`, and equivalent to ``bspline(x, 3)``.
      """
      x = cp.asarray(x)
  
      return _cubic_kernel(x)
  
label_desc: Use image node_id 2 for calling a global function with example usage: cubic(x) and returns: _cubic_kernel