DList$()$

$\{$

mHead $=$ mTail $=$ nullptr;

mSize $=0$;

$\}$

~DList$()$

$\{$

Clear$()$;

$\}$

DList$($const DList& $\_$copy$)$

$\{$

mHead $=$ nullptr;

mTail $=$ nullptr;

mSize $=0$;

$\}$

DList& operator$=($const DList& $\_$assign$)$

$\{$

$//$ TODO: Implement this method

$\}$

void AddHead$($const Type& $\_$data$)$

$\{$

$//$ TODO: Implement this method

$\}$

void AddTail$($const Type& $\_$data$)$

$\{$

$//$ TODO: Implement this method

$\}$

void Clear$()$

$\{$

$//$ TODO: Implement this method

$\}$

Iterator Insert$($Iterator& $\_$iter, const Type& $\_$data$)$

$\{$

$//$ Implement this method

$\}$

Iterator Erase$($Iterator& $\_$iter$)$

$\{$

$//$ TODO: Implement this method

$\}$

Iterator Begin$()$ const

$\{$

$//$ TODO: Implement this method

$\}$

Iterator End$()$ const

$\{$

$//$ TODO: Implement this method

$\}$

$\}$;