def export_pixels(image, photometry)
      raise ArgumentError, "Expected String, got #{photometry.class}." unless photometry.is_a?(String)
      image_module.export_pixels(image, photometry)
    end
def export_pixels(image, photometry)
      raise ArgumentError, "Expected String, got #{photometry.class}." unless photometry.is_a?(String)
      image_module.export_pixels(image, photometry)
    end
Extracts an array of pixels (integers) from an image object.

 @param [MagickImage] image a Magick image object
 @param [String] photometry a code describing the photometry of the pixel data (e.g. 'MONOCHROME1' or 'COLOR')
 @return [Array<Integer>] an array of pixel values