def draw(self):
        """Draws the checkbox."""
        if not self.visible:
            return

        # Blit the current checkbox's image.

        if self.isEnabled:
            if self.mouseIsDown and self.lastMouseDownOverButton and self.mouseOverButton:
                if self.value:
                    self.window.blit(self.surfaceOnDown, self.loc)
                else:
                    self.window.blit(self.surfaceOffDown, self.loc)
            else:
                if self.value:
                    self.window.blit(self.surfaceOn, self.loc)
                else:
                    self.window.blit(self.surfaceOff, self.loc)


        else:
            if self.value:
                self.window.blit(self.surfaceOnDisabled, self.loc)
            else:
                self.window.blit(self.surfaceOffDisabled, self.loc)
Draws the checkbox.