def get_ds_prop(propname):

    def _eval(params, ds):
        return getattr(ds, propname)
    cls = type(propname, (AnalysisTask,), dict(eval=_eval, _params=tuple()))
    return cls
def get_ds_prop(propname):

    def _eval(params, ds):
        return getattr(ds, propname)
    cls = type(propname, (AnalysisTask,), dict(eval=_eval, _params=tuple()))
    return cls