def _increment_diagonal_(A, value):
    """Increment the diagonal of an array by a value.

    Parameters
    ----------
    A : np.array
        The array whose diagonal will be extracted.

    value : number
        The value that will be incremented on the diagonal.


    Returns
    -------
    None.

    """
    d = A.diagonal()
    d.setflags(write=True)
    d += value
