'Get all Volumes associated with the current credentials.
:type volume_ids: list
:param volume_ids: Optional list of volume ids.  If this list
is present, only the volumes associated with
these volume ids 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.volume.Volume`
:return: The requested Volume objects'

def get_all_volumes(self, volume_ids=None, filters=None, dry_run=False):

    params = {}
    if volume_ids:
        self.build_list_params(params, volume_ids, 'VolumeId')
    if filters:
        self.build_filter_params(params, filters)
    if dry_run:
        params['DryRun'] = 'true'
    return self.get_list('DescribeVolumes', params, [('item', Volume)], verb='POST')
