Question: Use a package command in a maple procedure code

I can use a whole package in a procedure or a command from a package. 
Writing your own code needs sometimes external code from outside a procedure used ( a package..what else more?)
This i don't find back in the Maple helpfiles easily using external code in procedure  
 

 This old example uses display3d naming what is the same as display ( there is no display3d command in Maple ) 
It gives the error 

diskmethod(f,0,2,10,fig);
Error, (in with) package plots does not export display3d

The disk methode calculates 
V = int(Pi*f(x)^2, x = a .. b)

 The Code for diskmethoddisplay

diskmethod:=proc(f,a,b,N,figure::evaln)
  local X,Y,s,x,dX,i,disk;
  with(plots,display3d);
  X:=array(0..N);Y:=array(1..N);disk:=array(1..N);
  dX:=evalf((b-a)/N);
  X[0]:=a;s:=0;
  for i to N do
    X[i]:=a+i*dX; Y[i]:=evalf(f(X[i]));
    s:=s+evalf(Pi*Y[i]^2*dX);
    disk[i]:=plot3d([x,Y[i]*cos(theta),Y[i]*sin(theta)],
                x=X[i-1]..X[i],theta=0..2*Pi,grid=[2,51]):

  end do;
  figure:= display3d({seq(disk[i],i=1..N)},
            axes=box,projection=0.8,orientation=[-60,70]);
  print(`The approximate volume using`,N,`disks is V =`, s);
end proc: