node-handle(node-handle&& nh) noexcept;
Effects: Constructs a 
node-handle object initializing
ptr_ with 
nh.ptr_.  Move constructs 
alloc_ with
nh.alloc_.Assigns 
nullptr to 
nh.ptr_ and assigns
nullopt to 
nh.alloc_.node-handle& operator=(node-handle&& nh);
Preconditions: Either 
!alloc_, or
ator_traits::propagate_on_container_move_assignment::value
is 
true, or 
alloc_ ==  nh.alloc_. Effects: 
- If  ptr_ != nullptr- , destroys the  value_type- 
subobject in the  container_node_type-  object pointed to by  ptr_- 
by calling  ator_traits::destroy- , then deallocates  ptr_-  by
calling  ator_traits::template rebind_traits<container_node_type>::deallocate.
- If  !alloc_-  or  ator_traits::propagate_on_container_move_assignment::value- 
is  true- ,  - move assigns  nh.alloc_-  to  alloc_.
- Assigns
 nullptr-  to  nh.ptr_-  and assigns  nullopt-  to
 nh.alloc_.