code: def test_overwrite_subconfig():
      """Test that subconfig cannot be overwritten"""
      config = Configuration()
      config.nested = Configuration()
      with pytest.raises(ValueError) as exc:
          config.add_option("nested", option_type=str)
      assert "Configuration already contains nested" == str(exc.value)
  
      with pytest.raises(ValueError) as exc:
          config.nested = Configuration()
      assert (
          "Configuration already contains subconfiguration nested"
          == str(exc.value)
      )
  
imports: import argparse
  import logging
  import os
  import pytest
  import yaml
  from orion.core.io.config import Configuration, ConfigurationError
label_desc: Use image node_id 23 for calling a global function with example usage: test_overwrite_subconfig() without return types