Rama z-score failed  failed.

/net/marbles/raid1/dorothee/rerefine/cryoem/data_no_H/7r6m_24282/12_2023/7r6m_24282.pdb /net/marbles/raid1/dorothee/rerefine/cryoem/data_no_H/7r6m_24282/12_2023/7r6m_24282.map 3.68
Traceback (most recent call last):
  File "/net/marbles/raid1/dorothee/rerefine/cryoem/rerefine_script.py", line 440, in get_statistics
    self.json_data[p+'z_score'] = z_scores['W'][0]
TypeError: 'NoneType' object has no attribute '__getitem__'