'Get the transformation used for drawing y-axis labels, ticks
and gridlines.  The x-direction is in axis coordinates and the
y-direction is in data coordinates.
.. note::
This transformation is primarily used by the
:class:`~matplotlib.axis.Axis` class, and is meant to be
overridden by new kinds of projections that may need to
place axis elements in different locations.'

def get_yaxis_transform(self, which=u'grid'):

    if (which == u'grid'):
        return self._yaxis_transform
    elif (which == u'tick1'):
        return self.spines[u'left'].get_spine_transform()
    elif (which == u'tick2'):
        return self.spines[u'right'].get_spine_transform()
    else:
        raise ValueError(u'unknown    value    for    which')
