Crash with example null.vm

Traceback (most recent call last):
  File "vre-language/src/virtmat/language/utilities/errors.py", line 302, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/cli/run_model.py", line 113, in evaluate_prog
    print(f'program output: >>>\n{prog.value}\n<<<')
  File "/usr/lib/python3.10/functools.py", line 981, in __get__
    val = self.func(instance)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 211, in wrapper
    raise TextXError(str(err), **get_location_context(obj)) from err
textx.exceptions.TextXError: vre-language/examples/null.vm:3:1:  => 'a = (ints: null, 1) [MiB]
b = (floats: 1., null) [m]
c = (strings: '', null, 'blah')
d = (bool: true, null, false)
e = (nulls: null, null)
print(a, b, c, d, e)'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "python-3.10.12/bin/texts", line 8, in <module>
    sys.exit(texts())
  File "vre-language/src/virtmat/language/cli/__init__.py", line 25, in texts
    clargs.func(clargs)
  File "vre-language/src/virtmat/language/cli/run_model.py", line 156, in main
    evaluate_prog(prog)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/utilities/types.py", line 211, in wrapper
    return checktype_(func(obj), obj.type_)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 50, in program_value
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 50, in <listcomp>
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 125, in print_value
    return ' '.join(formatter(par.value) for par in self.params)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 125, in <genexpr>
    return ' '.join(formatter(par.value) for par in self.params)
  File "vre-language/src/virtmat/language/utilities/formatters.py", line 99, in formatter
    ret = formatter_series(val)
  File "vre-language/src/virtmat/language/utilities/formatters.py", line 60, in formatter_series
    values = ', '.join(formatter_numeric(v.magnitude) for v in val)
  File "vre-language/src/virtmat/language/utilities/formatters.py", line 60, in <genexpr>
    values = ', '.join(formatter_numeric(v.magnitude) for v in val)
  File "vre-language/src/virtmat/language/utilities/formatters.py", line 26, in formatter_numeric
    assert isinstance(magnitude, complex)
AssertionError