code: def _related(self, concept):
          
          return concept.hypernyms() + \
                  concept.hyponyms() + \
                  concept.member_meronyms() + \
                  concept.substance_meronyms() + \
                  concept.part_meronyms() + \
                  concept.member_holonyms() + \
                  concept.substance_holonyms() + \
                  concept.part_holonyms() + \
                  concept.attributes() + \
                  concept.also_sees() + \
                  concept.similar_tos()
docs: Returns related concepts for a concept.