code: def rgba_to_int(cls, red, green, blue, alpha):
          
          red = unwrap(red)
          green = unwrap(green)
          blue = unwrap(blue)
          alpha = unwrap(alpha)
          if red is None or green is None or blue is None:
              return None
          if alpha is None:
              alpha = 255
          r = red << 24
          g = green << 16
          b = blue << 8
          a = alpha << 0
          rgba_int = r+g+b+a
          if (rgba_int > (2**31-1)):       # convert to signed 32-bit int
              rgba_int = rgba_int - 2**32
          return rgba_int
docs: Encodes the color as an Integer in RGBA encoding
  
          Returns None if any of red, green or blue are None.
          If alpha is None we use 255 by default.
  
          :return:    Integer
          :rtype:     int