Load input

def interpret(self, msg):
        """ Load input """
        slides = msg.get('slides', [])
        self.cache = msg.get('folder', '.')
        self.gallery = msg.get('gallery', ['..'])
        self.finder.interpret(dict(galleries=self.gallery))

        # in case slides is a generator, turn it into a list
        # since I am going to go through it twice
        slides = [slide for slide in slides]

        logname = msg.get('logname')
        if logname:
            self.write_slide_list(logname, slides)

        # Now spin through slides again
        for slide in slides:

            image = self.draw_slide(slide)

            heading = slide['heading']['text']
            filename = self.get_image_name(heading)

            self.cache_image(filename, image)

        # fixme -- just return info in slides.txt as list of dicts
        return