code: def from_string(cls, rgb_hex_str):
          
          r = int(rgb_hex_str[:2], 16)
          g = int(rgb_hex_str[2:4], 16)
          b = int(rgb_hex_str[4:], 16)
          return cls(r, g, b)
docs: Return a new instance from an RGB color hex string like ``'3C2F80'``.