def get_max_width(self):
        return max([frame.image.width for frame in self.frames])
Parse a mixed list of declarations and at rules, as found eg.
dataset/ETHPy150Open ardekantur/pyglet/pyglet/image/__init__.py/Animation.get_max_width--crossover with--dataset/ETHPy150Open FichteFoll/CSScheme/tinycsscheme/tinycss/css21.py/CSS21Parser.parse_declarations_and_at_rules