def get_data_pm_1sigma(x, e=()):
    """
    Compute the 68.27% confidence interval given the 1-sigma measurement
    uncertainties `e` are given, else return a 2-tuple with data duplicated.

    Parameters
    ----------
    x: array-like
    e: optional, array-like or 2-tuple of array-like
        If array like, assume this is the 1-sigma measurement uncertainties
        If 2-tuple, assume these are the upper and lower confidence distance
        from the mean

    Returns
    -------

    """
    if e is None:
        return x, x

    n = len(e)
    if n == 0:
        return x, x
    if n == 2:
        return x - e[0], x + e[1]
    return x - e, x + e