some more type annotations that needed conditional imports

electrum/lnonion.py

@@ -24,7 +24,7 @@
 # SOFTWARE.
 
 import hashlib
-from typing import Sequence, List, Tuple, NamedTuple
+from typing import Sequence, List, Tuple, NamedTuple, TYPE_CHECKING
 from enum import IntEnum, IntFlag
 
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms
@@ -34,7 +34,9 @@ from . import ecc
 from .crypto import sha256, hmac_oneshot
 from .util import bh2u, profiler, xor_bytes, bfh
 from .lnutil import get_ecdh, PaymentFailure, NUM_MAX_HOPS_IN_PAYMENT_PATH, NUM_MAX_EDGES_IN_PAYMENT_PATH
-from .lnrouter import RouteEdge
+
+if TYPE_CHECKING:
+    from .lnrouter import RouteEdge
 
 
 HOPS_DATA_SIZE = 1300      # also sometimes called routingInfoSize in bolt-04
@@ -186,7 +188,7 @@ def new_onion_packet(payment_path_pubkeys: Sequence[bytes], session_key: bytes,
         hmac=next_hmac)
 
 
-def calc_hops_data_for_payment(route: List[RouteEdge], amount_msat: int, final_cltv: int) \
+def calc_hops_data_for_payment(route: List['RouteEdge'], amount_msat: int, final_cltv: int) \
         -> Tuple[List[OnionHopsDataSingle], int, int]:
     """Returns the hops_data to be used for constructing an onion packet,
     and the amount_msat and cltv to be used on our immediate channel.