detecting entities within a radius

[L.J.Duckfield]

I am having some trouble with my new block.

 

It needs to define a radius around itself and check whether any entity (creature / monster / player) is in the given radius.

 

i have been trying to use:-

if(world.getEntitiesWithinAABB, class, AxisAlignedBB){
//do something
}
else
{
//do something else
}

 

Any help would be greatly appreciated. Sorry if I'm missing something obvious.

[OvermindDL1]

world.getEntitiesWithinAABB is a function, and it returns a result as a List.