code: def exponential_kernel(
      distance: float, kernel_width: float = DEFAULT_KERNEL_WIDTH
  ) -> np.ndarray:
      """The exponential kernel."""
      return np.sqrt(np.exp(-(distance**2) / kernel_width**2))
  
label_desc: Use image node_id 2 for calling a global function with example usage: exponential_kernel(distance, kernel_width) and returns: np