:param: way string discribing if filter is for 'in' or 'out' messages
        :returns: list of zobjects.FilterRule

def get_filter_rules(self, way='in'):
        """
        :param: way string discribing if filter is for 'in' or 'out' messages
        :returns: list of zobjects.FilterRule
        """
        try:
            if way == 'in':
                filters = self.request(
                    'GetFilterRules')['filterRules']['filterRule']
            elif way == 'out':
                filters = self.request(
                    'GetOutgoingFilterRules')['filterRules']['filterRule']

            # Zimbra return a dict if there is only one instance
            if isinstance(filters, dict):
                filters = [filters]

            return [zobjects.FilterRule.from_dict(f) for f in filters]
        except KeyError:
            return []