def set_axes_labels(figure, axes_labels, points_number):
    """
    Set labels of axes for a single diagram.

    Parameters
    ----------
    figure : matplotlib.figure.Figure
        A single figure.
    axes_labels : tuple
        A tuple with two elements. Each one is a string which describes
        a single axis of a diagram.
    points_number : int
        A number of points used to construct one diagram.
    """
    figure.axes[0].set_title('Diagram for ' + str(points_number) +
        ' points', fontsize=20)
    figure.axes[0].set_xlabel(axes_labels[0], fontsize=15)
    figure.axes[0].set_ylabel(axes_labels[1], fontsize=15)
