<image> As shown in the figure, the graph of the linear function $$y = kx + b \ (k \neq 0)$$ intersects the graph of the inverse proportional function $$y = \dfrac{-2}{x}$$ at points $$A(-1, m)$$ and $$B(n, -1)$$. 
$$(1)$$ If $$C(x_{1}, y_{1})$$ and $$D(x_{2}, y_{2})$$ are two points on the graph of the inverse proportional function, and $$0 < x_{1} < x_{2}$$, compare the magnitudes of $$y_{1}$$ and $$y_{2}$$, with the relationship $$y_{1}$$ ______ $$y_{2}$$;
$$(2)$$ Find the expression of this linear function.