code: public <T> T get(String key, Class<T> type) {
          Object value = this.data.get(key);
          if (value != null && type.isAssignableFrom(value.getClass())) {
              return (T) value;
          }
          return null;
      }
docs: Access an attribute.
  
  @param type the attribute's type, not {@code null}
  @param key  the attribute's key, not {@code null}
  @return the attribute value, or {@code null}.