code: def _check_valid_data(self, data):
          
          if data.dtype.type != np.float32 and data.dtype.type != np.float64:
              raise ValueError('Must initialize normals clouds with a numpy float ndarray')
          if data.shape[0] != 3:
              raise ValueError('Illegal data array passed to normal cloud. Must have 3 coordinates')
          if len(data.shape) > 2:
              raise ValueError('Illegal data array passed to normal cloud. Must have 1 or 2 dimensions')
          if np.any((np.abs(np.linalg.norm(data, axis=0) - 1) > 1e-4) & (np.linalg.norm(data, axis=0) != 0)):
              raise ValueError('Illegal data array passed to normal cloud. Must have norm=1.0 or norm=0.0')
docs: Checks that the incoming data is a 3 x #elements ndarray of normal
          vectors.
  
          Parameters
          ----------
          data : :obj:`numpy.ndarray`
              The data to verify.
  
          Raises
          ------
          ValueError
              If the data is not of the correct shape or type, or if the vectors
              therein are not normalized.