from typing import TypeVar, Generic, Optional
import run_tests

T = TypeVar( 'T' )

class Tree( Generic[ T ] ):

    def __init__( self, value: T ) -> None:
        self.left  : Optional[ Tree[ T ] ] = None
        self.right : Optional[ Tree[ T ] ] = None
        self.value = value

    def rotate_left( self ) -> Any:
        assert self.left is not None
        r = self.left
        detach = r.right
        r.right = self
        self.left = detach
        return r

    def rotate_right( self ) -> Any:
        assert self.right is not None
        r = self.right
        detach = r.left
        r.left = self
        self.right = detach
        return r