def _infer_interval_breaks(coord):
    """
    >>> _infer_interval_breaks(np.arange(5))
    array([-0.5,  0.5,  1.5,  2.5,  3.5,  4.5])

    Taken from xarray.plotting.plot module
    """
    coord = np.asarray(coord)
    deltas = 0.5 * (coord[1:] - coord[:-1])
    first = coord[0] - deltas[0]
    last = coord[-1] + deltas[-1]
    return np.r_[[first], coord[:-1] + deltas, [last]]