def set_at(self, index, item):
check_not_none(item, "<STR_LIT>")<EOL>element_data = self._to_data(item)<EOL>return self._encode_invoke(list_set_codec, index=index, value=element_data)<EOL>
Replaces the specified element with the element at the specified position in this list.

:param index: (int), index of the item to be replaced.
:param item: (object), item to be stored.
:return: (object), the previous item in the specified index.