code: def pop(self, idx=None):
          
          if idx is not None:
              return self.database.run_script(
                  'array_remove',
                  keys=[self.key],
                  args=[idx])
          else:
              return self.database.run_script(
                  'array_pop',
                  keys=[self.key],
                  args=[])
docs: Remove an item from the array. By default this will be the
          last item by index, but any index can be specified.