removeAllElements method
Removes all entries in elements from this instances.
Implementation
void removeAllElements(Iterable<E> elements) {
  for (var e in elements) {
    removeElement(e);
  }
}Removes all entries in elements from this instances.
void removeAllElements(Iterable<E> elements) {
  for (var e in elements) {
    removeElement(e);
  }
}