code: def down(self, down_uid):
          '''
          Download the entity by UID.
          '''
          down_url = MPost.get_by_uid(down_uid).extinfo.get('tag__file_download', '')
          print('=' * 40)
          print(down_url)
          str_down_url = str(down_url)[15:]
  
  
          if down_url:
              ment_id = MEntity.get_id_by_impath(str_down_url)
              if ment_id:
                  MEntity2User.create_entity2user(ment_id, self.userinfo.uid)
              return True
          else:
              return Falsf down(self, down_uid):
          '''
          Download the entity by UID.
          '''
          down_url = MPost.get_by_uid(down_uid).extinfo.get('tag__file_download', '')
          print('=' * 40)
          print(down_url)
          str_down_url = str(down_url)[15:]
  
  
          if down_url:
              ment_id = MEntity.get_id_by_impath(str_down_url)
              if ment_id:
                  MEntity2User.create_entity2user(ment_id, self.userinfo.uid)
              return True
          else:
              return False
docs: Download the entity by UID.