code: def load_system_config(config_file=None, work_dir=None, allow_missing=False):
      
      docker_config = _get_docker_config()
      if config_file is None:
          config_file = "bcbio_system.yaml"
      if not os.path.exists(config_file):
          base_dir = get_base_installdir()
          test_config = os.path.join(base_dir, "galaxy", config_file)
          if os.path.exists(test_config):
              config_file = test_config
          elif allow_missing:
              config_file = None
          else:
              raise ValueError("Could not find input system configuration file %s, "
                               "including inside standard directory %s" %
                               (config_file, os.path.join(base_dir, "galaxy")))
      config = load_config(config_file) if config_file else {}
      if docker_config:
          assert work_dir is not None, "Need working directory to merge docker config"
          config_file = os.path.join(work_dir, "%s-merged%s" % os.path.splitext(os.path.basename(config_file)))
          config = _merge_system_configs(config, docker_config, config_file)
      if "algorithm" not in config:
          config["algorithm"] = {}
      config["bcbio_system"] = config_file
      return config, config_file
docs: Load bcbio_system.yaml configuration file, handling standard defaults.
  
      Looks for configuration file in default location within
      final base directory from a standard installation. Handles both standard
      installs (galaxy/bcbio_system.yaml) and docker installs (config/bcbio_system.yaml).