def METHOD_NAME(self) -> None:
    if self.impl._split_proportion:
        if self.interface.direction == self.interface.VERTICAL:
            position = self.impl._split_proportion * self.frame.size.width
        else:
            position = self.impl._split_proportion * self.frame.size.height
        self.setPosition(position, ofDividerAtIndex=0)
        self.impl._split_proportion = None