docs: def iterconfig(config, scan_type):
      '''
      Iterate over BIDS configuration file
      '''
      if scan_type in config:
          for modality,scans in iter(config[scan_type].items()):
              for scan in scans:
                  scan.update({
                      'type': scan_type,
                      'modality': modality
                  })
                  yield scan