<image>As shown in the figure, the lateral surface of a cone is cut open along a generatrix and flattened, forming a sector. If the radius of the base of the cone is $$r = 2 \, \text{cm}$$ and the central angle of the sector is $$\theta = 120^\circ$$, the length of the generatrix (slant height) $$$l$$ of the cone is ______. 