'Test whether the mouse event occurred in the y axis.
Returns *True* | *False*'

def contains(self, mouseevent):

    if callable(self._contains):
        return self._contains(self, mouseevent)
    (x, y) = (mouseevent.x, mouseevent.y)
    try:
        trans = self.axes.transAxes.inverted()
        (xaxes, yaxes) = trans.transform_point((x, y))
    except ValueError:
        return (False, {})
    (l, b) = self.axes.transAxes.transform_point((0, 0))
    (r, t) = self.axes.transAxes.transform_point((1, 1))
    inaxis = ((yaxes >= 0) and (yaxes <= 1) and (((x < l) and (x > (l - self.pickradius))) or ((x > r) and (x < (r + self.pickradius)))))
    return (inaxis, {})
