code: public static void isAssignable(Class<?> superType, Class<?> subType) throws IllegalArgumentException {
  		isAssignable(superType, subType, "{} is not assignable to {})", subType, superType);
  	}
docs: 断言 {@code superType.isAssignableFrom(subType)} 是否为 {@code true}.
  
  <pre class="code">
  Assert.isAssignable(Number.class, myClass);
  </pre>
  
  @param superType 需要检查的父类或接口
  @param subType 需要检查的子类
  @throws IllegalArgumentException 如果子类非继承父类，抛出此异常