'Create a manager with various queues and a used IP blacklist
:param queues: ``dict`` A dictionary containing queue names for keys
and CIDR specifications for values.
:param used_ips: ``set`` A set of IP addresses which are marked as used
and unassignable. Any iterable will be coerced into a set to remove
duplicate entries.'

def __init__(self, queues=None, used_ips=None):

    if (queues is None):
        queues = {}
    if (used_ips is None):
        used_ips = set()
    self._used_ips = set(used_ips)
    self._queues = queues
    self._networks = {}
    for (name, cidr) in queues.items():
        self.load(name, cidr)
