Conversion from Petri net to process tree - Assertion Error

[OleSeifert]

I am trying to run conformance checking using alignments on models mined by the inductive miner. To speed up the process, I am converting the Petri net to a process tree first. When trying to run this conversion, I get an assertion error.

Version: pm4py 2.7.13.1
OS: Ubuntu
Python: 3.12.2

Code to reproduce:

if __name__ == "__main__":
    event_log = read_xes(EVENT_LOG_PATH)

    pnml_path = os.path.join(PETRI_NET_FOLDER_PATH, pnml_file)

    petri_net, inital_marking, final_marking = pnml_importer.apply(pnml_path)

    tree = pm4py.convert_to_process_tree(petri_net, inital_marking, final_marking)

Where EVENT_LOG_PATH and PETRI_NET_FOLDER_PATH are constants pointing to the corresponding file paths.

The Error:

Traceback (most recent call last):
  File "/home/ole/conformance_checking/conformance_inductive_trees.py", line 144, in <module>
    main()
  File "/home/ole/conformance_checking/conformance_inductive_trees.py", line 107, in main
    tree = pm4py.convert_to_process_tree(petri_net, inital_marking, final_marking)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/convert.py", line 265, in convert_to_process_tree
    tree = to_process_tree.apply(net, im, fm)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/conversion/wf_net/variants/to_process_tree.py", line 367, in apply
    pt = parse(pt_str)
         ^^^^^^^^^^^^^
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 234, in parse
    return parse_recursive(string_rep, depth_cache, depth)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  [Previous line repeated 3 more times]
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 311, in parse_recursive
    parse_recursive((string_rep.strip())[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  [Previous line repeated 1 more time]
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 311, in parse_recursive
    parse_recursive((string_rep.strip())[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
...
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 286, in parse_recursive
    parse_recursive(string_rep[1:], depth_cache, depth)
  [Previous line repeated 2 more times]
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 311, in parse_recursive
    parse_recursive((string_rep.strip())[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 311, in parse_recursive
    parse_recursive((string_rep.strip())[1:], depth_cache, depth)
  File "/home/ole/anaconda3/envs/conf/lib/python3.12/site-packages/pm4py/objects/process_tree/utils/generic.py", line 295, in parse_recursive
    assert (string_rep.startswith('tau') or string_rep.startswith('τ') or string_rep.startswith(u'\u03c4'))
AssertionError

This pattern repeats multiple times...

The .pnml file used can be found under Petri net