def area_rhombus(diagonal_1: float, diagonal_2: float) -> float:
    """
    Calculate the area of a rhombus.

    >>> area_rhombus(10, 20)
    100.0
    >>> area_rhombus(-1, -2)
    Traceback (most recent call last):
        ...
    ValueError: area_rhombus() only accepts non-negative values
    >>> area_rhombus(1, -2)
    Traceback (most recent call last):
        ...
    ValueError: area_rhombus() only accepts non-negative values
    >>> area_rhombus(-1, 2)
    Traceback (most recent call last):
        ...
    ValueError: area_rhombus() only accepts non-negative values
    """
    if diagonal_1 < 0 or diagonal_2 < 0:
        raise ValueError("area_rhombus() only accepts non-negative values")
    return 1 / 2 * diagonal_1 * diagonal_2