Use correct nottion for an optional positional argument.
@@ -522,7 +522,7 @@ class KgtkReader(KgtkFormat, ClosableIter[typing.List[str]]):
@classmethod
def add_shared_arguments(cls, parser: ArgumentParser):
- parser.add_argument(dest="kgtk_file", help="The KGTK file to read", type=Path, default=None)
+ parser.add_argument(dest="kgtk_file", help="The KGTK file to read", type=Path, nargs="?")
parser.add_argument( "--allow-comment-lines", dest="ignore_comment_lines",
help="When specified, do not ignore comment lines.", action='store_false')
