code: def _setitem_with_key_seq(self, key_seq, value):
          
          table = self
          key_so_far = tuple()
          for key in key_seq[:-1]:
              key_so_far += (key,)
              self._make_sure_table_exists(key_so_far)
              table = table[key]
          table[key_seq[-1]] = value
docs: Sets a the value in the TOML file located by the given key sequence.
  
          Example:
          self._setitem(('key1', 'key2', 'key3'), 'text_value')
          is equivalent to doing
          self['key1']['key2']['key3'] = 'text_value'