def _set_pos(self, pos):
        """
        Set current position for scroll bar.
        """
        if self._h < len(self._options):
            pos *= len(self._options) - self._h
            pos = int(round(max(0, pos), 0))
            self._start_line = pos
def _set_pos ( self , pos ) : if self . _h < len ( self . _options ) : pos *= len ( self . _options ) - self . _h pos = int ( round ( max ( 0 , pos ) , 0 ) ) self . _start_line = pos
Set current position for scroll bar.