Define the category of the class.

        # Arguments
            category: The name of category.

        # Returns:
            PygalleBaseClass: An instance of :class:`PygalleBaseClass`

def set_category(self, category: str = None) -> 'PygalleBaseClass':
        """ Define the category of the class.

        # Arguments
            category: The name of category.

        # Returns:
            PygalleBaseClass: An instance of :class:`PygalleBaseClass`
        """
        return self.set_internal(PygalleBaseClass.__KEYS.CATEGORY, category)