mp == 0) {
    return _root.value;
  }
  int modificationCount = _modificationCount;
  int splayCount = _splayCount;
  V value = ifAbsent();
  if (modificationCount != _modificationCount) {
    throw new ConcurrentModificationError(this);
  }
  if (splayCount != _splayCount) {
    comp = _splay(key);
    &#47;&#47; Key is still not there, otherwise _modificationCount would be changed.
    assert(comp != 0);
  }
  _addNewRoot(new _SplayTreeMapNode(key, value), comp);
  return value;
}</code></pre>
    </sect