'*locator* : the bbox returned from the locator is used as a
initial axes location. If None, axes.bbox is used.
*extend* : same as in ColorbarBase
*orientation* : same as in ColorbarBase'

def __init__(self, locator=None, extend=u'neither', orientation=u'vertical'):

    self._locator = locator
    self.extesion_fraction = 0.05
    self.extend = extend
    self.orientation = orientation
