The current src code depends on PyPerplan to parse the PDDL File. PyPerplan is lightweight STRIPS planner written in Python. It is an undergrad student project, so its developers did not have much software engineering experience.
Further, PyPerplan supports some version of PDDL 2.x . To add support to more recent syntax updates, it is recommended to upgrade the parser to this PDDL Parser, which supports PDDL 3.1. It includes support for
derived predicates,
numeric costs,
conditional effects,
non-deterministic effects (for FOND - not officially included PDDL 3.1 syntax yet), and