pub fn back_mut(&mut self) -> Option<&mut A::Item> {
        let len = self.len();
        if !self.is_empty() {
            Some(&mut self[len - 1])
        } else {
            None
        }
    }
/// Provides a mutable reference to the back element, or `None` if the
/// sequence is empty.
///
/// # Examples
///
/// ```
/// use arraydeque::ArrayDeque;
///
/// let mut buf: ArrayDeque<[_; 2]> = ArrayDeque::new();
///
/// buf.push_back(1);
/// buf.push_back(2);
///
/// assert_eq!(buf.back_mut(), Some(&mut 2));
/// ```
Provides a mutable reference to the back element, or `None` if the
sequence is empty.
Provides a mutable reference to the back element or ` None ` if the sequence is empty .
pub fn back_mut(&mut self) -> Option<&mut A::Item> {
        let len = self.len();
        if !self.is_empty() {
            Some(&mut self[len - 1])
        } else {
            None
        }
    }
pub fn back_mut ( & mut self ) -> Option < & mut A :: Item > { let len = self . len ( ) ; if ! self . is_empty ( ) { Some ( & mut self [ len - 1 ] ) } else { None } }
Provides a mutable reference to the back element, or `None` if the
sequence is empty.
Provides a mutable reference to the back element or ` None ` if the sequence is empty .
&mut self
examples
```
use arraydeque::ArrayDeque.

let mut buf: ArrayDeque<[_; 2]> = ArrayDeque::new().




` ` ` use arraydeque :: ArrayDeque . let mut buf : ArrayDeque< [ _ ; 2 ] > = ArrayDeque :: new () .