code: def map_to_index(param_list, prefix=[], d=None):
      if d is None:
          d = {}
      for i, obj in enumerate(param_list):
          trailer = [Subscript(Number(unicode(i)))]
          if isinstance(obj, list):
              map_to_index(obj, trailer, d=d)
          else:
              d[obj] = prefix + trailer
      return d
  
file_path: catboost/contrib/tools/python/src/Lib/lib2to3/fixes/fix_tuple_params.py
imports: from ..None import pytree
  from ..pgen2 import token
  from ..None import fixer_base
  from ..fixer_util import Assign, Name, Newline, Number, Subscript, syms
label_desc: Use image node_id 4 for calling a global function with example usage: map_to_index(param_list, prefix, d) and returns: d