chore(trezorlib): Support payment requests and GetNonce command.

python/.changelog.d/1430.added

@@ -0,0 +1 @@
+Support payment requests and GetNonce command.

python/src/trezorlib/btc.py

@@ -255,6 +255,7 @@ def sign_tx(
     outputs: Sequence[messages.TxOutputType],
     details: Optional[messages.SignTx] = None,
     prev_txes: Optional["TxCacheType"] = None,
+    payment_reqs: Sequence[messages.TxAckPaymentRequest] = (),
     preauthorized: bool = False,
     **kwargs: Any,
 ) -> Tuple[Sequence[Optional[bytes]], bytes]:
@@ -354,8 +355,12 @@ def sign_tx(
         else:
             current_tx = this_tx
 
+        if res.request_type == R.TXPAYMENTREQ:
+            assert res.details.request_index is not None
+            msg = payment_reqs[res.details.request_index]
+            res = client.call(msg)
+        else:
             msg = messages.TransactionType()
-
             if res.request_type == R.TXMETA:
                 msg = copy_tx_meta(current_tx)
             elif res.request_type in (R.TXINPUT, R.TXORIGINPUT):
@@ -364,7 +369,9 @@ def sign_tx(
             elif res.request_type == R.TXOUTPUT:
                 assert res.details.request_index is not None
                 if res.details.tx_hash:
-                msg.bin_outputs = [current_tx.bin_outputs[res.details.request_index]]
+                    msg.bin_outputs = [
+                        current_tx.bin_outputs[res.details.request_index]
+                    ]
                 else:
                     msg.outputs = [current_tx.outputs[res.details.request_index]]
             elif res.request_type == R.TXORIGOUTPUT:

python/src/trezorlib/misc.py

@@ -108,3 +108,8 @@ def decrypt_keyvalue(
             iv=iv,
         )
     )
+
+
+@expect(messages.Nonce, field="nonce", ret_type=bytes)
+def get_nonce(client: "TrezorClient"):
+    return client.call(messages.GetNonce())