Duplicates not detected when parsing typed lists

[marcofavorito]

Subject of the issue

Duplicates in typed lists, e.g. in the (:types ...) section of a PDDL domain, are not detected, whereas we should signal to client code there a syntactic problem in the PDDL domain definition.

Your environment

• OS: Ubuntu 22.04
• Python version: 3.10.9
• Package Version: 0.3.1, tag v0.3.1

Steps to reproduce

Run the following code:

domain_str = """
    (define (domain test)
        (:requirements :typing)
        (:types a b c a)
    )"""
domain = DomainParser()(domain_str)

Expected behaviour

An error is raised signalling that the PDDL file has syntactic problems.

Actual behaviour

The PDDL file is parsed without any issue.