code: def listdir(self, pattern=None):
          
          if pattern is None:
              pattern = '*'
          return [
              self / child
              for child in map(self._always_unicode, os.listdir(self))
              if self._next_class(child).fnmatch(pattern)
          ]
docs: D.listdir() -> List of items in this directory.
  
          Use :meth:`files` or :meth:`dirs` instead if you want a listing
          of just files or just subdirectories.
  
          The elements of the list are Path objects.
  
          With the optional `pattern` argument, this only lists
          items whose names match the given pattern.
  
          .. seealso:: :meth:`files`, :meth:`dirs`