Cooldown on a command

how can i put a cooldown on it ? for the first command that respawns you like to appear in the screen " 2 minutes till you can respawn

    --E call/skip emergency
    group = 0, 
	pressed = function() 
	  if vRP.isInComa({}) then
	    if called == 0 then
	      HKserver.canSkipComa({},function(skipper)
		    if skipper then
		      HKserver.docsOnline({},function(docs)
		        if docs == 0 then
				  vRP.killComa({})
			    else
				  called = 30
				  local x,y,z = table.unpack(GetEntityCoords(GetPlayerPed(-1),true))
				  HKserver.helpComa({x,y,z})
			    end
			  end)
            end
		  end)
		else
		  vRP.notify({"~r~You already called the ambulance."})
		end
	  end
	end,
	released = function()
	  --Do nothing on release because it's toggle.
	end,
  },