code: def delenv():
      """Delete options in the existing environment."""
      if not local._env:
          raise EnvError("No GDAL environment exists")
      else:
          local._env.clear_config_options()
  
      local._env.stop()
      local._env = None
  
imports: from functools import wraps, total_ordering
  from inspect import getfullargspec
  import logging
  import os
  import re
  import threading
  import warnings
  import attr
  from fiona._env import GDALDataFinder, GDALEnv, PROJDataFinder, calc_gdal_version_num, get_gdal_config, get_gdal_release_name, get_gdal_version_num, set_gdal_config, set_proj_data_search_path
  from fiona.errors import EnvError, FionaDeprecationWarning, GDALVersionError
  from fiona.session import Session, DummySession
label_desc: Use image node_id 6 for calling a global function with example usage: delenv() without return types