from typing import Tuple


def get_transfer_distance(
        client,
        start,
        end,
        mode='driving',
) -> Tuple[int, int]:
    """Get the distance and duration of a transfer.
    Args:
        client (Client): A googlemaps API client.
        start (string): The starting point, either lat,long as a string or an address.
        end (string): The ending point, either lat,long as a string or an address.
        mode (string): The transporation method, driving by default.
    Returns:
        (int, int): Returns a tuple of the distance in kilometers and the
            duration in seconds.
    """
    driving_distances = client.distance_matrix(start, end, mode=mode)
    elements = driving_distances['rows'][0]['elements'][0]
    km = elements['distance']['value']
    duration = elements['duration']['value']
    return km, duration