def _advance(self):
        """
        Advance one element, setting L{_x}, L{_atstart} and L{_atend}
        """
        try:
            self._atstart = False
            self._x = self._g.next()
        except __HOLE__:
            self._x = None
            self._atend = True
dataset/ETHPy150Open mobify/iterstuff/iterstuff/lookahead.py/Lookahead._advance