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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 ces(subsystem, mechanisms=False, purviews=False, cause_purviews=False, effect_purviews=False, parallel=False):
 """Return the conceptual structure of this subsystem, optionally restricted to concepts with the mechanisms and purviews given in keyword arguments. If you don't need the full |CauseEffectStructure|, restricting the possible mechanisms and purviews can make this function much faster. Args: subsystem (Subsystem):
 The subsystem for which to determine the |CauseEffectStructure|. Keyword Args: mechanisms (tuple[tuple[int]]):
 Restrict possible mechanisms to those in this list. purviews (tuple[tuple[int]]):
 Same as in |Subsystem.concept()|. cause_purviews (tuple[tuple[int]]):
 Same as in |Subsystem.concept()|. effect_purviews (tuple[tuple[int]]):
 Same as in |Subsystem.concept()|. parallel (bool):
 Whether to compute concepts in parallel. If ``True``, overrides :data:`config.PARALLEL_CONCEPT_EVALUATION`. Returns: CauseEffectStructure: A tuple of every |Concept| in the cause-effect structure. """

    if mechanisms is False:
        mechanisms = utils.powerset(subsystem.node_indices, nonempty=True)

    engine = ComputeCauseEffectStructure(mechanisms, subsystem, purviews,
                                         cause_purviews, effect_purviews)

    return CauseEffectStructure(engine.run(parallel or
                                           config.PARALLEL_CONCEPT_EVALUATION),
                                subsystem=subsystem)