def get_instances(self, urns):
# parse slice names and sliver ids
names = set()
ids = set()
for urn in urns:
xrn = OSXrn(xrn=urn)
if xrn.type == 'slice':
names.add(xrn.get_slice_name())
elif xrn.type == 'sliver':
ids.add(xrn.leaf)
# look up instances
instances = []
filter = {}
if names:
filter['name'] = names
if ids:
filter['id'] = ids
servers = self.driver.shell.nova_manager.servers.findall(**filter)
instances.extend(servers)
return instances
