@category.setter<EOL><INDENT>def category(self, categories):<DEDENT>
if isinstance(categories, list):<EOL><INDENT>for c in categories:<EOL><INDENT>self.add_category(c)<EOL><DEDENT><DEDENT>else:<EOL><INDENT>self.add_category(categories)<EOL><DEDENT>
Add categories assigned to this message

        :rtype: list(Category)