code: def __missing__(self, key):
      return f"{{{key}}}"
  
imports: from collections import defaultdict
  from itertools import count
  import numpy
  from ..operands import TensorFuse
  from ..None import arithmetic, reduction
  from ..array_utils import as_same_device
  from .core import TensorFuseChunkMixin
label_desc: Use image node_id 1 for calling the _Default obj's underlying member method code with example usage: obj.__missing__(key) and returns: str, key, str