class_docstr: provide attribute-style access to a nested dict
class_docstr_tok: ["provide","attribute-style","access","to","a","nested","dict"]
code: def __getattr__(self, key):
      prefix = object.__getattribute__(self, "prefix")
      if prefix:
          prefix += "."
      prefix += key
      try:
          v = object.__getattribute__(self, "d")[key]
      except KeyError:
          raise OptionError("No such option")
      if isinstance(v, dict):
          return DictWrapper(v, prefix)
      else:
          return _get_option(prefix)
  
imports: from collections import namedtuple
  from contextlib import contextmanager
  import re
  import warnings
  import pandas.compat
  from pandas.compat import lmap, map, u
label_desc: Use image node_id 3 for calling the DictWrapper obj's underlying member method code with example usage: obj.__getattr__(key) and returns: DictWrapper, _get_option