IndexError: list index out of range ontology annotation

Question

I am adding annotation to ontology using following code

from owlready import *
onto = get_ontology("C://Users//sharm//Documents//ISWC2020//Ontology_read_play//Covid_v1.owl")
ANNOTATIONS[Thing].add_annotation("comment", "My comment")
onto.save()

Then it shows an IndexError, when I have save it using onto.save()

IndexError Traceback (most recent call last)<module>
--> onto.save()

C:\ProgramData\Anaconda3\lib\site-packages\owlready\__init__.py in save(self, filename)
282     owl = to_owl(self)
283     if filename: f = open(filename, "w")
--> 284     else:        f = _open_onto_file(self.base_iri, self.name, "w")
285     print("* Owlready * Saving ontology %s to %s..." % (self.name, getattr(f, "name", "???")), file = sys.stderr)
286     f.write(owl)

C:\ProgramData\Anaconda3\lib\site-packages\owlready\__init__.py in _open_onto_file(base_iri, name, mode, only_local)
199     if os.path.exists(filename): return open(filename, mode)
200   if (mode == "r") and not only_local: return urllib.request.urlopen(base_iri)
--> 201   if (mode == "w"): return open(os.path.join(onto_path[0], "%s.owl" % name), "w")
202   raise FileNotFoundError
203 

IndexError: list index out of range

Answer 1

Quick search on the doc (https://pythonhosted.org/Owlready2/onto.html) shows that if you don't specify a file or a filename in the save method, it uses the first path in onto_path module variable. You never set it up and apparently onto_path starts empty.

Add the appropriate name parameter to the save method and checkout the doc next time you have problems.