When I run this code it gives me error Usage: ema(X, window). window must be at least 2

version: 1.30.16

@state

defg atr1(high,low,close,atr_tp){

mf_atr = 2 * atr_tp - 1

tr = rowMax(abs(high-low),abs(high-prev(close)),abs(low-prev(close)))

atr_inc = ema(tr, (mf_atr))

return (atr_inc)

}

select *, atr(high,low,close,atr_tp) from tmp

tmp = table(100:0,`symbol`open`high`low`close,[SYMBOL,DOUBLE,DOUBLE,DOUBLE ,DOUBLE])

op1 = table(100:0,`symbol`atr,[SYMBOL,DOUBLE])

atr=createReactiveStateEngine(name="atr",metrics=<[atr1(high,low,close,7)]>,dummyTable =tmp,outputTable=op1,keyColumn=`symbol);