core/src/main/java/com/twitter/elephantbird/util/ThriftUtils.java
private static void verifyAncestry(Class<?> tClass) {
    if (!TBase.class.isAssignableFrom(tClass)) {
      Utils.ensureClassLoaderConsistency(TBase.class, tClass.getClassLoader());
      throw new ClassCastException(tClass.getName() + " is not a Thrift class");
    }
  }
private static void verifyAncestry(Class<?> tClass) {
    if (!TBase.class.isAssignableFrom(tClass)) {
      Utils.ensureClassLoaderConsistency(TBase.class, tClass.getClassLoader());
      throw new ClassCastException(tClass.getName() + " is not a Thrift class");
    }
  }
Verify that clazz is a Thrift class. i.e. is a subclass of TBase