code: def tree(self, expand=False, level=None):
          
  
          return TreeViewer(self, expand=expand, level=level)
docs: Provide a ``print``-able display of the hierarchy.
  
          Parameters
          ----------
          expand : bool, optional
              Only relevant for HTML representation. If True, tree will be fully expanded.
          level : int, optional
              Maximum depth to descend into hierarchy.
  
          Examples
          --------
          >>> import zarr
          >>> g1 = zarr.group()
          >>> g2 = g1.create_group('foo')
          >>> g3 = g1.create_group('bar')
          >>> g4 = g3.create_group('baz')
          >>> g5 = g3.create_group('quux')
          >>> d1 = g5.create_dataset('baz', shape=100, chunks=10)
          >>> g1.tree()
          /
           ├── bar
           │   ├── baz
           │   └── quux
           │       └── baz (100,) float64
           └── foo
          >>> g1.tree(level=2)
          /
           ├── bar
           │   ├── baz
           │   └── quux
           └── foo
          >>> g3.tree()
          bar
           ├── baz
           └── quux
               └── baz (100,) float64
  
          Notes
          -----
          Please note that this is an experimental feature. The behaviour of this
          function is still evolving and the default output and/or parameters may change
          in future versions.