Node color as Hex Triplet https://en.wikipedia.org/wiki/Web_colors#Hex_triplet

def color_hex(self):
        """Node color as Hex Triplet https://en.wikipedia.org/wiki/Web_colors#Hex_triplet"""
        def clamp(x):
            return max(0, min(int(x), 255))

        r, g, b = np.trunc(self.color_rgb * 255)
        return "#{0:02x}{1:02x}{2:02x}".format(clamp(r), clamp(g), clamp(b))