[sv-bc] quary about semaphore

Hi,
I have query regarding the following testcase::

module semaphore16 (input [7:0] in1,in2, output reg [7:0] 
out1,out2,out3,out4);
class semaExtend extends semaphore;
real r;
shortreal sr;
time t;
function bit [1:0] func(input reg [15:0] rg);
r = rg;
sr = rg;
t = rg;
func = ++rg;
endfunction
endclass
semaExtend p = new(-11);
always @(in1,in2)
begin
  out1 = p.func(in1^in2);
  out2 = p.r;
  out3 = p.sr;
  out4 = p.t;
end
endmodule
Is it necessary to define new() method : function new (int keycount = 0);
                                                                       
super.new(keycount);
                                                                       
endfunction
in derived class.

Thanx
Soumya