CI failing

[daico007]

Bug summary

The CI on the main branch is failing due to recent changes in treelib. Impacted test:

    def test_show_hierarchy(self, capsys):
        # test that the output written to the screen is correct
        temp_particle = mb.Compound(name="C", element="C")
        temp_particle.print_hierarchy()
    
        captured = capsys.readouterr()
>       assert captured.out.strip() == "C, 1 particles, 0 bonds, 0 children"
E       assert "b'C, 1 parti... children\\n'" == 'C, 1 particl...s, 0 children'
E         - C, 1 particles, 0 bonds, 0 children
E         + b'C, 1 particles, 0 bonds, 0 children\n'
E         ? ++