Traceback (most recent call last):
  File "C:\Users\vince\OneDrive\Documenti\GitHub\fuzzy_dl_owl2_testing\converter.py", line 14, in <module>
    translate_owl2_to_fdl("./results/nominal_test.owl", "nominal_test.fdl")
  File "C:\Users\vince\OneDrive\Documenti\GitHub\fuzzy_dl_owl2_testing\converter.py", line 6, in translate_owl2_to_fdl
    fdl.translate_owl2ontology()
  File "C:\Users\vince\miniconda3\Lib\site-packages\fuzzy_dl_owl2\fuzzyowl2\fuzzyowl2.py", line 190, in translate_owl2ontology
    self.process_concept_annotations()
  File "C:\Users\vince\miniconda3\Lib\site-packages\fuzzy_dl_owl2\fuzzyowl2\fuzzyowl2.py", line 342, in process_concept_annotations
    concept: ConceptDefinition = FuzzyOwl2XMLParser.parse_string(
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\vince\miniconda3\Lib\site-packages\fuzzy_dl_owl2\fuzzyowl2\parser\owl2_xml_parser.py", line 142, in parse_string
    float(
TypeError: float() argument must be a string or a real number, not 'NoneType'