code: def test_key_to_arg():
      """Test the key to arg function"""
      cmdline_parser = CmdlineParser()
      assert cmdline_parser._key_to_arg("c") == "-c"
      assert cmdline_parser._key_to_arg("test") == "--test"
      assert cmdline_parser._key_to_arg("test-test") == "--test-test"
  
file_path: orion/tests/unittests/core/io/test_cmdline_parser.py
imports: import os
  from collections import OrderedDict
  import pytest
  from orion.core.io.cmdline_parser import CmdlineParser
label_desc: Use image node_id 4 for calling a global function with example usage: test_key_to_arg() without return types