def ivy(self, bootstrap_workunit_factory=None):
    """Returns an ivy instance bootstrapped by this bootstrapper.

    :param bootstrap_workunit_factory: the optional workunit to bootstrap under.
    :raises: Bootstrapper.Error if ivy could not be bootstrapped
    """
    return Ivy(self._get_classpath(bootstrap_workunit_factory),
               ivy_settings=self._ivy_subsystem.get_options().ivy_settings,
               ivy_resolution_cache_dir=self._ivy_subsystem.resolution_cache_dir(),
               extra_jvm_options=self._ivy_subsystem.extra_jvm_options())
Returns an ivy instance bootstrapped by this bootstrapper.

    :param bootstrap_workunit_factory: the optional workunit to bootstrap under.
    :raises: Bootstrapper.Error if ivy could not be bootstrapped