ESGF loader fails with new changes to run_RCMES.py

Reading the configuration file  configuration_files/ESGF_example/ESGF-Example.yaml
Loading observation datasets:
[{'dataset_id': 'obs4MIPs.CNES.AVISO.zos.mon.v20110829|esgf-data.jpl.nasa.gov', 'name': 'AVISO', 'loader_name': 'ESGF', 'variable_name': 'zos'}]
Traceback (most recent call last):
  File "run_RCMES.py", line 101, in <module>
    obs_datasets = load_datasets_from_config(*obs_data_info, **kwargs)
  File "run_RCMES.py", line 40, in load_datasets_from_config
    if password is None: