'Render this Pipeline as a DAG.
Parameters
format : {\'svg\', \'png\', \'jpeg\'}
Image format to render with.  Default is \'svg\'.'

@expect_element(format=('svg', 'png', 'jpeg'))
def show_graph(self, format='svg'):

    g = self.to_simple_graph('', AssetExists())
    if (format == 'svg'):
        return g.svg
    elif (format == 'png'):
        return g.png
    elif (format == 'jpeg'):
        return g.jpeg
    else:
        raise AssertionError(('Unknown    graph    format    %r.' % format))
