Invalid syntax (Python 3.10 issue)

Hello, thanks for this amazing package. When trying to run this using python 3.10 I first get some errors about collections.Iterator that are easily fixed, but then I got this : ``` $ python -m mixt.examples.simple Traceback (most recent call last): File "/usr/lib/python3.10/runpy.py", line 187, in _run_module_as_main mod_name, mod_spec, code = _get_module_details(mod_name, _Error) File "/usr/lib/python3.10/runpy.py", line 157, in _get_module_details code = loader.get_code(mod_name) File "<frozen importlib._bootstrap_external>", line 1017, in get_code File "<frozen importlib._bootstrap_external>", line 947, in source_to_code File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed File "/home/max/projects/mixt/src/mixt/examples/simple.py", line 29 print(render_example()) SyntaxError: invalid syntax ```