Python 3.13 changes the behaviour of locals() to prevent modifications (see PEP 558 and 667).

In the CLI where we have

    for letter in string.ascii_lowercase:
        locals()[letter] = letter
    eval_spec = eval(spec)
    plot_spec(eval_spec)

this causes the eval to run without any of the variables available and the tests fail with NameErrors.

Acceptance Criteria

• Tests should pass