def check_recipe(self, recipe):
    if ('gpl' in recipe.get('about/license').lower()):
        if (not recipe.get('about/license_file', '')):
            self.message('about/license')
def check_recipe(self, recipe):
    if ('gpl' in recipe.get('about/license').lower()):
        if (not recipe.get('about/license_file', )):
            self.message('about/license')