docs: def load_environment_vars(self):
          """
          Looks for any MACH9_ prefixed environment variables and applies
          them to the configuration if present.
          """
          for k, v in os.environ.items():
              if k.startswith(MACH9_PREFIX):
                  _, config_key = k.split(MACH9_PREFIX, 1)
                  self[config_key] = v