code: def _select_options(pat):
      """returns a list of keys matching `pat`
  
      if pat=="all", returns all registered options
      """
  
      # short-circuit for exact key
      if pat in _registered_options:
          return [pat]
  
      # else look through all of them
      keys = sorted(_registered_options.keys())
      if pat == "all":  # reserved key
          return keys
  
      return [k for k in keys if re.search(pat, k, re.I)]
  
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 9 for calling a global function with example usage: _select_options(pat) and returns: unknown, list, keys