$[4$ Marks$]$

Write a code to create generic data structure called deque which consists of a list of items. The following operations are performed in deque

a$.$ push $(x)$ : Insert item $x$ on the front of the deque.

b$.$ pop$()$ : Remove the front item from the deque and return it$.$

c$.$ inject $(x)$ : Insert item $x$ on the rear end of the deque.

d$.$ eject$($x$)$: Remove the rear item from the deque and return it$.$