If $y = y ( x )$ is the solution of the differential equation $x \frac { d y } { d x } + 2 y = x e ^ { x } , y ( 1 ) = 0$ then the local maximum value of the function $z ( x ) = x ^ { 2 } y ( x ) - e ^ { x } , x \in R$ is\\
(1) $1 - e$\\
(2) 0\\
(3) $\frac { 1 } { 2 }$\\
(4) $\frac { 4 } { e } - e$