'Returns an instance of the configured IPAM driver
:param subnet_pool: Subnet pool of the address space to use.
:type subnet_pool: dict
:returns: An instance of Driver for the given subnet pool'

@classmethod
def get_instance(cls, subnet_pool, context):

    ipam_driver_name = cfg.CONF.ipam_driver
    mgr = manager.NeutronManager
    driver_class = mgr.load_class_for_provider('neutron.ipam_drivers', ipam_driver_name)
    return driver_class(subnet_pool, context)
