Rama z-score failed  failed.

/net/cci-nas-00/data/ceres_data/9nbc_49226/04_2026/9nbc_49226.cif /net/cci-nas-00/data/ceres_data/9nbc_49226/04_2026/9nbc_49226.map 2.87
Traceback (most recent call last):
  File "/net/cci-filer3/home/dcliebschner/04_cryoem/CERES/rerefine_script.py", line 421, in get_statistics
    self.json_data[p+'z_score'] = z_scores['W'][0]
TypeError: 'NoneType' object is not subscriptable