code: def empty_environ():
      for k in DASH_ENV_VARS.keys():
          if k in os.environ:
              os.environ.pop(k)
  
imports: import os
  import pytest
  import dash
  from dash._configs import DASH_ENV_VARS
label_desc: Use image node_id 1 for calling a global function with example usage: empty_environ() without return types