code: public void check(final int api) {
          if (api == Opcodes.ASM4) {
              if (visibleTypeAnnotations != null
                      && visibleTypeAnnotations.size() > 0) {
                  throw new RuntimeException();
              }
              if (invisibleTypeAnnotations != null
                      && invisibleTypeAnnotations.size() > 0) {
                  throw new RuntimeException();
              }
              for (FieldNode f : fields) {
                  f.check(api);
              }
              for (MethodNode m : methods) {
                  m.check(api);
              }
          }
      }
docs: Checks that this class node is compatible with the given ASM API version.
  This methods checks that this node, and all its nodes recursively, do not
  contain elements that were introduced in more recent versions of the ASM
  API than the given version.
  
  @param api
  an ASM API version. Must be one of {@link Opcodes#ASM4} or
  {@link Opcodes#ASM5}.