length: int 
length: int = 10

width: float 
width: float = 100

name: str 
name: str = "rectangle"

is_square: bool 
is_square: bool = False

x: List[int] = [1, 2]
a: List[float] = [1.0, 4.6, 9.1]

x: Dict[str, float] = {'length': 10.0, 'width': 100.0}

x: Set[str] = {'rect', 'square'}

x: Tuple[str, float, float] = ("rect", 10.0, 100.0)

a: Any
a = None    # type: Any
a = []      # OK
a = 2       # OK

def add_two_integers_or_floats(x: Union[int, float], y: Union[int, float]) -> Union[int, float]:
    return x + y

aux : Optional[str]: #Union[X, None]
aux = None

F = List[float] # Aliasing list of floats
a: F = [1.0, 4.6, 9.1]