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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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())