code: def linf_norm(a: np.array) -> float:
      """
      Calculate L-inf norm for an array.
  
      Parameters
      ----------
      a: np.ndarray
           The array to calculate the L-inf on.
  
      Returns
      -------
      float
          The norm.
      """
      assert a.ndim == 1, "Check that 'linf_norm' receives a 1D array."
      return np.linalg.norm(a, ord=np.inf)
  
label_desc: Use image node_id 3 for calling a global function with example usage: linf_norm(a) and returns: np