code: def read_ix(ix, **kwargs):
      
      if not isinstance(ix, ixmp.TimeSeries):
          error = 'not recognized as valid ixmp class: {}'.format(ix)
          raise ValueError(error)
  
      df = ix.timeseries(iamc=False, **kwargs)
      df['model'] = ix.model
      df['scenario'] = ix.scenario
      return df, 'year', []
docs: Read timeseries data from an ixmp object
  
      Parameters
      ----------
      ix: ixmp.TimeSeries or ixmp.Scenario
          this option requires the ixmp package as a dependency
      kwargs: arguments passed to ixmp.TimeSeries.timeseries()