code: @Override
      public void visitCode(Code obj) {
          state = State.SAW_NOTHING;
          lvt = obj.getLocalVariableTable();
          if ((lvt != null) && prescreen(getMethod())) {
              super.visitCode(obj);
          }
      }
docs: implements the visitor to set the state on entry of the code block to SAW_NOTHING, and to see if there is a local variable table
  
  @param obj
  the context object of the currently parsed code block