code: def __getitem__(cls, fn):
      return cls(fn)
  
imports: import copyreg
  import functools
  import inspect
  import operator
  import warnings
  from functools import reduce
  from weakref import WeakValueDictionary
  import funsor.ops
  from funsor.ops.builtin import parse_ellipsis, parse_slice
  from funsor.util import broadcast_shape, get_backend, get_tracing_state, quote
label_desc: Use image node_id 1 for calling the DependentMeta obj's underlying member method code with example usage: obj.__getitem__(cls, fn) and returns: cls