Add appropriate type annotations to learning.py and use appropriate devices while restoring saved state.
"""Learner for the IMPALA actor-critic agent."""
import time
-from typing import Callable, Dict, Iterator, List, NamedTuple, Tuple, Optional, Sequence
+from typing import Callable, Dict, Iterator, List, NamedTuple, Optional, Sequence, Tuple
import acme
from acme import specs
