def __init__(
     self,
     ax,
     cmap=None,
     norm=None,
     alpha=None,
     values=None,
     boundaries=None,
     orientation='vertical',
     ticklocation='auto',
     extend='neither',
     spacing='uniform',  # uniform or proportional
     ticks=None,
     _format=None,
     drawedges=False,
     filled=True,
     extendfrac=None,
     extendrect=False,
     label='',
 ):
     ColorbarBase.__init__(self, ax, cmap, norm, alpha, values, boundaries,
                           orientation, ticklocation, extend, spacing,
                           ticks, _format, drawedges, filled, extendfrac,
                           extendrect, label)
     ScalarMappable.__init__(self, norm, cmap)