def set_axis_labels(ax, xlabel=None, ylabel=None, title=None):
    """Sets the labels for a single axis

    :param ax: axis object
    :param xlabel: string for the x label of the axis
    :param ylabel: string for the y label of the axis
    :param title: title for the axis
    :returns: ax
    """
    if xlabel is not None:
        ax.set_xlabel(xlabel)
    if ylabel is not None:
        ax.set_ylabel(ylabel)
    if title is not None:
        ax.set_title(title)
    return ax