code: def available():
      return sorted(registry.list_problems())
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from tensor2tensor.data_generators import all_problems
  from tensor2tensor.utils import registry
label_desc: Use image node_id 2 for calling a global function with example usage: available() and returns: sorted