Design and implement a class representing a doubly linked list. The class must have the following requirements: 1. The linked list and the nodes must be implemented as C++ templates

1. The list must be generic it should not implement arithmetic/logic functions.

2. It must include a destructor, a copy constructor and operator=

3. It must include methods to insert at the front and at the back of the list

4. It must include a method to return the length of the list

5. It must provide an iterator-based interface for the user from front to back 6. It must include an iterator-based interface for the user from back to front