Use of function and packages in testbench

Hi,
I written VHDL function as package,how to use that function in testbench 
code.
function to_max(a, b : integer) return integer is
  variable output :integer;
  begin
if (a > b)then
 output := a;
  return output ;
  else
output := b;
  return output;
  end if;
Thanks in advance

Regards
Raghvendra