def tearDown(self):
     for inst in self.instances:
         common_functions.delete_instance(self.nova, inst)
     self.instances = []
     for fip in self.floating_ips:
         common_functions.delete_floating_ip(self.nova, fip)
     self.floating_ips = []
     for volume in self.volumes:
         self.os_conn.delete_volume(volume)
     self.volumes = []
     for flavor in self.flavors:
         common_functions.delete_flavor(self.nova, flavor.id)
     self.flavors = []
     for key in self.keys:
         common_functions.delete_keys(self.nova, key.name)
     self.keys = []
     self.os_conn.delete_security_group(self.sec_group)