'Sets the value of ``list`` specified by ``index`` to the given ``value``.
Index ``0`` means the first position, ``1`` the second and so on.
Similarly, ``-1`` is the last position, ``-2`` second last, and so on.
Using an index that does not exist on the list causes an error.
The index can be either an integer or a string that can be converted to
an integer.
Example:
| Set List Value | ${L3} | 1  | xxx |
| Set List Value | ${L3} | -1 | yyy |
| ${L3} = [\'a\', \'xxx\', \'yyy\']'

def set_list_value(self, list_, index, value):

    try:
        list_[self._index_to_int(index)] = value
    except IndexError:
        self._index_error(list_, index)
