code: def clean(inst):
      
      
      if (inst.clean_level == 'dusty') | (inst.clean_level == 'clean'):
          idx, = np.where(inst['B_flag'] == 0)
          inst.data = inst[idx, :]
  
      return None
docs: Routine to return VEFI data cleaned to the specified level
  
      Parameters
      -----------
      inst : (pysat.Instrument)
          Instrument class object, whose attribute clean_level is used to return
          the desired level of data selectivity.
  
      Returns
      --------
      Void : (NoneType)
          data in inst is modified in-place.
  
      Notes
      --------
      'dusty' or 'clean' removes data when interpolation flag is set to 1