'Create an allocation pool for the subnet.
This method does not perform any validation on parameters; it simply
persist data on the database.
:param pool_start: string expressing the start of the pool
:param pool_end: string expressing the end of the pool
:return: the newly created pool object.'

def create_pool(self, context, pool_start, pool_end):

    ip_pool_obj = ipam_objs.IpamAllocationPool(context, ipam_subnet_id=self._ipam_subnet_id, first_ip=pool_start, last_ip=pool_end)
    ip_pool_obj.create()
    return ip_pool_obj
