'List security groups in the current region.
:keyword ex_filters: security group attributes to filter results.
:type ex_filters: ``dict``
:return: a list of defined security groups
:rtype: ``list`` of ``ECSSecurityGroup``'

def ex_list_security_groups(self, ex_filters=None):

    params = {'Action': 'DescribeSecurityGroups', 'RegionId': self.region}
    if (ex_filters and isinstance(ex_filters, dict)):
        ex_filters.update(params)
        params = ex_filters
    def _parse_response(resp_object):
        sg_elements = findall(resp_object, 'SecurityGroups/SecurityGroup', namespace=self.namespace)
        sgs = [self._to_security_group(el) for el in sg_elements]
        return sgs
    return self._request_multiple_pages(self.path, params, _parse_response)
