'A predicate, set on object initialization, that takes a :class:`.Host`
and returns a value. If the value is falsy, the :class:`.Host` is
:class:`~HostDistance.IGNORED`. If the value is truthy,
:class:`.HostFilterPolicy` defers to the child policy to determine the
host\'s distance.
This is a read-only value set in ``__init__``, implemented as a
``property``.'

@property
def predicate(self):

    return self._predicate
