from qsiprep.workflows.dwi.base import init_dwi_preproc_wf
wf = init_dwi_preproc_wf(scan_groups={'dwi_series': ['fake.nii'],
                          'fieldmap_info': {'suffix': None},
                          'dwi_series_pedir': 'j'},
                         output_prefix='',
                         source_file='/data/bids/sub-1/dwi/sub-1_dwi.nii.gz')