code: def test_key_value_label():
      """unit tests for specific cases of key and value label conversion."""
      assert "face" == u.key_label("--face")
      assert "fa_ce" == u.key_label("------fA.!! ce")
  
      # Empty string roundtrips.
      assert "" == u.key_label("")
      assert "" == u.value_label("")
  
      # keys can't have leading digits, just letters, so we append a k.
      assert "k0helper" == u.key_label("--0helper")
  
      # values CAN have leading digits and underscores.
      assert "0helper" == u.value_label("--0helper")
      assert "_helper" == u.value_label("--_helper")
  
file_path: caliban/tests/caliban/platform/cloud/test_util.py
imports: import re
  import hypothesis.strategies
  from hypothesis import given
  import caliban.platform.cloud.util
label_desc: Use image node_id 2 for calling a global function with example usage: test_key_value_label() without return types