docs: def norm(vec):
      """Compute the (standard l2) norm of a vector.
  
      Parameters
      ----------
      vec: array of shape (dim,)
  
      Returns
      -------
      The l2 norm of vec.
      """
      result = 0.0
      for i in range(vec.shape[0]):
          result += vec[i] ** 2
      return np.sqrt(result)