def to_cartesian(algebraic):
    """Convert algebraic to cartesian

    Parameters
    ----------
    algebraic: str
        Algebraic coordinate

    Returns
    -------
    tuple
        Cartesian coordinate
    """
    mapper = {
        'A': 1,
        'B': 2,
        'C': 3,
        'D': 4,
        'E': 5,
        'F': 6,
        'G': 7,
        'H': 8}

    hor = mapper[algebraic[0]]
    ver = int(algebraic[1])

    return (hor, ver)