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