question: public Instance placeSymbol ( Symbol symbol , Transform matrix2 , AlphaTransform cxform , int ratio , int clipDepth ) { Transform matrix = matrix2 ; int depth = timeline . getAvailableDepth ( ) ; Instance inst = new Instance ( symbol , depth ) ; timeline . setAvailableDepth ( depth + 1 ) ; if ( matrix == null ) { matrix = new Transform ( ) ; } Placement placement = new Placement ( inst , matrix , cxform , null , ratio , clipDepth , frameNumber , false , false , null ) ; placements . add ( placement ) ; return inst ; }
target:  Place a symbol at the next available depth with the given properties.