'Get the shapes of the outputs.'

def get_output_shapes(self):

    outputs = self.execs[0].outputs
    shapes = [out.shape for out in outputs]
    concat_shapes = []
    for (key, the_shape, axis) in zip(self.symbol.list_outputs(), shapes, self.output_layouts):
        the_shape = list(the_shape)
        if (axis >= 0):
            the_shape[axis] = self.batch_size
        concat_shapes.append((key, tuple(the_shape)))
    return concat_shapes
