rm uncessary warning making noisy to check if contig length was defined

ppanggolin/genome.py

@@ -553,8 +553,6 @@ def __setitem__(self, coordinate: Tuple[int, int, str], gene: Gene):
     @property
     def length(self) -> Union[int, None]:
         """Get the length of the contig"""
-        if self._length is None:
-            logging.getLogger("PPanGGOLiN").warning("Contig length is unknown")
         return self._length
 
     @length.setter