code: def _GetVisibilityPolicy():
    
    try:
      visibility_config = yaml_data_visibility_config_reader.OpenAndRead()
    except yaml_data_visibility_config_reader.Error as err:
      return error_data_visibility_policy.ErrorDataVisibilityPolicy(
          'Could not process debugger config: %s' % err)
  
    if visibility_config:
      return glob_data_visibility_policy.GlobDataVisibilityPolicy(
          visibility_config.blacklist_patterns,
          visibility_config.whitelist_patterns)
  
    return None
docs: If a debugger configuration is found, create a visibility policy.