'Adjust the axes and return a list of information about the Sankey
subdiagram(s).
Return value is a list of subdiagrams represented with the following
fields:
Field             Description
*patch*           Sankey outline (an instance of
:class:`~maplotlib.patches.PathPatch`)
*flows*           values of the flows (positive for input, negative
for output)
*angles*          list of angles of the arrows [deg/90]
For example, if the diagram has not been rotated,
an input to the top side will have an angle of 3
(DOWN), and an output from the top side will have
an angle of 1 (UP).  If a flow has been skipped
(because its magnitude is less than *tolerance*),
then its angle will be *None*.
*tips*            array in which each row is an [x, y] pair
indicating the positions of the tips (or "dips") of
the flow paths
If the magnitude of a flow is less the *tolerance*
for the instance of :class:`Sankey`, the flow is
skipped and its tip will be at the center of the
diagram.
*text*            :class:`~matplotlib.text.Text` instance for the
label of the diagram
*texts*           list of :class:`~matplotlib.text.Text` instances
for the labels of flows
.. seealso::
:meth:`add`'

def finish(self):

    self.ax.axis([(self.extent[0] - self.margin), (self.extent[1] + self.margin), (self.extent[2] - self.margin), (self.extent[3] + self.margin)])
    self.ax.set_aspect(u'equal', adjustable=u'datalim')
    return self.diagrams
