'Returns a list of :class:`EC2NetworkSubnet` objects for the
current region.
:param      subnet_ids: Returns only subnets matching the provided
subnet IDs. If not specified, a list of all
the subnets in the corresponding region
is returned.
:type       subnet_ids: ``list``
:param      filters: The filters so that the list returned includes
information for certain subnets only.
:type       filters: ``dict``
:rtype:     ``list`` of :class:`EC2NetworkSubnet`'

def ex_list_subnets(self, subnet_ids=None, filters=None):

    params = {'Action': 'DescribeSubnets'}
    if subnet_ids:
        params.update(self._pathlist('SubnetId', subnet_ids))
    if filters:
        params.update(self._build_filters(filters))
    return self._to_subnets(self.connection.request(self.path, params=params).object)
