minor error class and type checking fixes

lbry/lbry/extras/daemon/exchange_rate_manager.py

@@ -72,7 +72,7 @@ class AioHttpManager:
     async def get_response_body(self):
         response = await asyncio.wait_for(self._make_request(), self.REQUESTS_TIMEOUT)
         if self.content_type not in response.headers.get('Content-Type'):
-            raise InvalidExchangeRateResponse(self.url, f'Received response is not of type {self.content_type}')
+            raise InvalidExchangeRateResponseError(self.url, f'Received response is not of type {self.content_type}')
         return response.read().decode()
 
 

lbry/lbry/wallet/manager.py

@@ -1,5 +1,6 @@
 import os
 import json
+import typing
 import logging
 from binascii import unhexlify
 from typing import Optional, List
@@ -15,13 +16,16 @@ from lbry.wallet.account import Account
 from lbry.wallet.ledger import MainNetLedger
 from lbry.wallet.transaction import Transaction, Output
 from lbry.wallet.database import WalletDatabase
-from lbry.extras.daemon.exchange_rate_manager import ExchangeRateManager
 from lbry.conf import Config
 
 
 log = logging.getLogger(__name__)
 
 
+if typing.TYPE_CHECKING:
+    from lbry.extras.daemon.exchange_rate_manager import ExchangeRateManager
+
+
 class LbryWalletManager(BaseWalletManager):
 
     def __init__(self, *args, **kwargs):
@@ -195,7 +199,8 @@ class LbryWalletManager(BaseWalletManager):
         return tx
 
     async def create_purchase_transaction(
-            self, accounts: List[Account], txo: Output, exchange: ExchangeRateManager, override_max_key_fee=False):
+            self, accounts: List[Account], txo: Output, exchange: 'ExchangeRateManager',
+            override_max_key_fee=False):
         fee = txo.claim.stream.fee
         fee_amount = exchange.to_dewies(fee.currency, fee.amount)
         if not override_max_key_fee and self.config.max_key_fee:

lbry/tests/unit/lbrynet_daemon/test_ExchangeRateManager.py

@@ -310,5 +310,5 @@ class TestAioHttpManager(AsyncioTestCase):
         manager = exchange_rate_manager.AioHttpManager('some url', 'some params', 'json')
         with unittest.mock.patch.object(
                 exchange_rate_manager.AioHttpManager, '_make_request', make_request_mock
-        ), self.assertRaises(InvalidExchangeRateResponse):
+        ), self.assertRaises(InvalidExchangeRateResponseError):
             await manager.get_response_body()