public List<String> getDispatcherKeysForProperty(String propertyKey, @Nullable String propertyValue) {
    ImmutableList.Builder<String> keys = ImmutableList.builder();
    for (NotificationDispatcherMetadata metadata : dispatchersMetadata) {
      String dispatcherKey = metadata.getDispatcherKey();
      String value = metadata.getProperty(propertyKey);
      if (value != null && (propertyValue == null || value.equals(propertyValue))) {
        keys.add(dispatcherKey);
      }
    }
    return keys.build();
  }
@Test
  public void shouldReturnDispatcherKeysForSpecificPropertyValue() {
    assertThat(underTest.getDispatcherKeysForProperty("global", "true")).containsOnly("Dispatcher1", "Dispatcher2");
  }