5.8. Type Aliases

5.8.1. Type Aliases

from typing import List, Tuple


GeographicCoordinate = Tuple[float, float]

locations: List[GeographicCoordinate] = [
    (25.91375, -60.15503),
    (-11.01983, -166.48477),
    (-11.01983, -166.48477)
]

from typing import Union


AllowedTypes = Union[list, set, tuple]

def my_print(args: AllowedTypes) -> None:
    if not isinstance(args, AllowedTypes.__args__):
        raise TypeError(f'Collection must be instance of {AllowedTypes.__args__}')

    for element in collection:
        print(element)

5.8.2. Type Vars

from typing import TypeVar, Iterable, Tuple

T = TypeVar('T', int, float, complex)
Vector = Iterable[Tuple[T, T]]

def inproduct(v: Vector[T]) -> T:
    return sum(x*y for x, y in v)

def dilate(v: Vector[T], scale: T) -> Vector[T]:
    return ((x * scale, y * scale) for x, y in v)

vec = []  # type: Vector[float]