<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _load_environment_vars(self):
 # type: () -> None """Loads configuration from environment variables """

        self._config[kinds.ENV_VAR].update(
            self._normalized_keys(":env:", self._get_environ_vars())
        )