def remove_spines(ax, sides):
    """
    Remove spines of axis.

    Parameters:
      ax: axes to operate on
      sides: list of sides: top, left, bottom, right

    Examples:
    removespines(ax, ['top'])
    removespines(ax, ['top', 'bottom', 'right', 'left'])
    """
    for side in sides:
        ax.spines[side].set_visible(False)
    return ax