def _sanitize_values(arr):
    """
    return an ndarray for our input,
    in a platform independent manner
    """

    if hasattr(arr, 'values'):
        arr = arr.values
    else:

        # scalar
        if is_scalar(arr):
            arr = [arr]

        # ndarray
        if isinstance(arr, np.ndarray):
            pass

        elif is_list_like(arr) and len(arr) > 0:
            arr = maybe_convert_platform(arr)

        else:
            arr = np.asarray(arr)

    return arr