Why am I getting error: could not find function or function reference 'study'?

Question

//DeMark_9_Indicator_Wealth_Insider
study("DeMark9 Indicator",overlay=true)
TD = close > close[4] ?nz(TD[1])+1:0
TS = close < close[4] ?nz(TS[1])+1:0
TDUp = TD - valuewhen(TD < TD[1], TD , 1 )
TDDn = TS - valuewhen(TS < TS[1], TS , 1 )
plotshape(TDUp==7?true:na,style=shape.triangledown,text="7",color=green,location=location.abovebar)
plotshape(TDUp==8?true:na,style=shape.triangledown,text="8",color=green,location=location.abovebar)
plotshape(TDUp==9?true:na,style=shape.triangledown,text="⚠️",color=green,location=location.abovebar)
plotshape(TDDn==7?true:na,style=shape.triangleup,text="7",color=red,location=location.belowbar)
plotshape(TDDn==8?true:na,style=shape.triangleup,text="8",color=red,location=location.belowbar)
plotshape(TDDn==9?true:na,style=shape.triangleup,text="✅",color=red,location=location.belowbar)

On line 2, I receive a could not find function or function reference 'study' I don't know why. This is for TradingView, and its Pine Script.

Answer 1

study() is now called indicator() in pine script v5.

I had the same problem, found the answer buried deep in the release notes.