code: def fix_shapes(self):
          
          for i in xrange(self.n_chunks):
              for side in ['left', 'right', 'top', 'bottom']:
                  edge = getattr(self, side).ravel()[i]
                  if side in ['left', 'right']:
                      shp = [edge.todo.size, 1]
                  else:
                      shp = [1, edge.todo.size]
                  edge.done = edge.done.reshape(shp)
                  edge.data = edge.data.reshape(shp)
                  edge.todo = edge.todo.reshape(shp)
docs: Fixes the shape of the data fields on edges. Left edges should be
          column vectors, and top edges should be row vectors, for example.