def index(self, value, start=None, stop=None):
<EOL>return self._list.index(value, start, stop)<EOL>
Return the smallest *k* such that `keysview[k] == value` and `start <= k
< end`.  Raises `KeyError` if *value* is not present.  *stop* defaults
to the end of the set.  *start* defaults to the beginning.  Negative
indexes are supported, as for slice indices.