void erase(iterator iter) {
			auto it = iter.get_pointer();
			if (it == nullptr) {
				throw std::invalid_argument("no element");
			}
			if (it->left == nullptr && it->right == nullptr) {
				if (it->parent->left == it) {
					it->parent->left = nullptr;
				}
				if(it->parent->right == it) {
					it->parent->right = nullptr;
				}
				Node<T>* temp = it;
				it = nullptr;
				delete  temp;
				--size_;
				return;
			}
			if (it->left == nullptr && it->right!=nullptr) {
				if (it->parent->left == it) {
					it->parent->left = it->right;
					it->right->parent = it->parent;
				}
				else if (it->parent->right == it) {
					it->parent->right = it->right;
					it->right->parent = it->parent;
				}
				Node<T>* temp = it;
				it = nullptr;
				delete  temp;
				--size_;
				return;
			}
			if (it->left != nullptr && it->right == nullptr) {
				if (it->parent->left == it) {
					it->parent->left = it->left;
					it->left->parent = it->parent;
				}
				else if (it->parent->right == it) {
					it->parent->right = it->left;
					it->left->parent = it->parent;
				}
				Node<T>* temp = it;
				it = nullptr;
				delete  temp;
				--size_;
				return;
			}
			if (it->left != nullptr && it->right != nullptr) {
				Node<T>* min=(++iter).get_pointer();
				it->value = min->value;
				erase(iterator(min));

			}
		}