more type annotations in core lib

electrum/exchange_rate.py

@@ -17,6 +17,8 @@ from .i18n import _
 from .util import PrintError, ThreadJob, make_dir, log_exceptions
 from .util import make_aiohttp_session
 from .network import Network
+from .simple_config import SimpleConfig
+
 
 # See https://en.wikipedia.org/wiki/ISO_4217
 CCY_PRECISIONS = {'BHD': 3, 'BIF': 0, 'BYR': 0, 'CLF': 4, 'CLP': 0,
@@ -434,7 +436,7 @@ def get_exchanges_by_ccy(history=True):
 
 class FxThread(ThreadJob):
 
-    def __init__(self, config, network):
+    def __init__(self, config: SimpleConfig, network: Network):
         self.config = config
         self.network = network
         if self.network: