code: def max_pathlen(self):
          
  
          pathlen = self.pathlen
          if self.parent is None:
              return pathlen
  
          max_parent = self.parent.max_pathlen
  
          if max_parent is None:
              return pathlen
          elif pathlen is None:
              return max_parent - 1
          else:
              return min(self.pathlen, max_parent - 1)
docs: The maximum pathlen for any intermediate CAs signed by this CA.
  
          This value is either ``None``, if this and all parent CAs don't have a ``pathlen`` attribute, or an
          ``int`` if any parent CA has the attribute.