调用函数报错

为什么call_formula('单股模型示范',600004,'1d',start_time="",end_time="",count=-1,dividend_type="none",extend_param={})

报错RuntimeError: func:subscribeFormulaSync, error:{ "error" : { "params" : { "ErrorID" : 300000, "ErrorMsg" : "[xtquant]formula not exists: 单股模型示范" }, "status" : 1 } }