code: def concept(self, mechanism, purviews=False, cause_purviews=False,
                  effect_purviews=False):
          
          cause = self.cause_system.mic(
              mechanism, purviews=(cause_purviews or purviews))
  
          effect = self.effect_system.mie(
              mechanism, purviews=(effect_purviews or purviews))
  
          return Concept(mechanism=mechanism, cause=cause, effect=effect,
                         subsystem=self)
docs: Compute a concept, using the appropriate system for each side of the
          cut.