'Get all Availability Zones associated with the current region.
:type zones: list
:param zones: Optional list of zones.  If this list is present,
only the Zones associated with these zone names
will be returned.
:type filters: dict
:param filters: Optional filters that can be used to limit
the results returned.  Filters are provided
in the form of a dictionary consisting of
filter names as the key and filter values
as the value.  The set of allowable filter
names/values is dependent on the request
being performed.  Check the EC2 API guide
for details.
:type dry_run: bool
:param dry_run: Set to True if the operation should not actually run.
:rtype: list of :class:`boto.ec2.zone.Zone`
:return: The requested Zone objects'

def get_all_zones(self, zones=None, filters=None, dry_run=False):

    params = {}
    if zones:
        self.build_list_params(params, zones, 'ZoneName')
    if filters:
        self.build_filter_params(params, filters)
    if dry_run:
        params['DryRun'] = 'true'
    return self.get_list('DescribeAvailabilityZones', params, [('item', Zone)], verb='POST')
