code: def _is_made_of_nones(obj):
      """Checks if `obj` is a nested structure of `None`s."""
      elems = tree_flatten(obj)
      # Returning False for an empty list, because it doesn't have any Nones inside.
      return elems and all(x is None for x in elems)
  
file_path: trax/trax/fastmath/numpy.py
imports: import numpy
  from scipy.special import logsumexp
  from trax.shapes import signature
label_desc: Use image node_id 16 for calling a global function with example usage: _is_made_of_nones(obj) and returns: unknown