'Start the instances specified
:type instance_ids: list
:param instance_ids: A list of strings of the Instance IDs to start
:type dry_run: bool
:param dry_run: Set to True if the operation should not actually run.
:rtype: list
:return: A list of the instances started'

def start_instances(self, instance_ids=None, dry_run=False):

    params = {}
    if instance_ids:
        self.build_list_params(params, instance_ids, 'InstanceId')
    if dry_run:
        params['DryRun'] = 'true'
    return self.get_list('StartInstances', params, [('item', Instance)], verb='POST')
