help needed

in this afl buy sell arrow not coming pls help me .

_SECTION_BEGIN("bf");
CLN= Ref(C,3);
Beh=((CLN - EMA(CLN, 10)) / EMA(CLN, 10)) * 100;
Plot(0,"",colorBlack,styleLine);
V2 = HHV(Beh,100);
V3 = LLV(Beh,100);
Beh1= WMA(Beh*(V2-V3),6);
Plot(Beh1, " bsf ",4,4);
Buy = Beh1>0;
Sell = Beh1<0;
Filter = Buy OR Sell;
Buy=ExRem(Buy,Sell);
Sell=ExRem(Sell,Buy);
AddColumn(Beh1,"bsf");
AddColumn(Buy, "Buy");
AddColumn(Sell, "Sell");
PlotShapes(IIf(Buy, shapeUpArrow, shapeNone),colorWhite, 0,L, Offset=-10);
PlotShapes(IIf(Sell, shapeDownArrow, shapeNone),colorWhite, 0,H, Offset=-10);
_SECTION_END();

Provide your Conditions for Buy-sell arrows.

Buy = Beh1>0;
Sell = Beh1<0;