Fix linter

Fix whitespace
Fix main window imports for linter
Update dlg_configureExplorer.py

src/mainApp.py

@@ -154,4 +154,4 @@ def onSignVerifyMessage(self):
         # Create Dialog
         ui = SignMessage_dlg(self.mainWindow)
         if ui.exec():
-            printDbg("Sign/Verify message...")
+            printDbg("Sign/Verify message...")

src/mainWindow.py

@@ -13,12 +13,12 @@
 from PyQt5.QtCore import pyqtSignal, Qt, QThread
 from PyQt5.QtGui import QPixmap, QColor, QPalette, QTextCursor, QFont, QIcon
 from PyQt5.QtWidgets import QWidget, QPushButton, QHBoxLayout, QGroupBox, QVBoxLayout, \
-    QFileDialog, QTextEdit, QTabWidget, QLabel, QSplitter, QAction, QMenuBar
+    QFileDialog, QTextEdit, QTabWidget, QLabel, QSplitter
 
 from apiClient import ApiClient
 from constants import starting_height, DefaultCache, wqueue
 from hwdevice import HWdevice
-from misc import printDbg, printException, printOK, getCallerName, getFunctionName, \
+from misc import printDbg, printException, printOK, saveCacheSettings, getCallerName, getFunctionName, \
     WriteStreamReceiver, now, persistCacheSetting, myPopUp_sb, getRemotePET4Lversion
 
 from tabRewards import TabRewards
@@ -191,7 +191,7 @@ def getRPCserver(self):
 
     def getServerListIndex(self, server):
         return self.header.rpcClientsBox.findData(server)
-    
+
     def getExplorerListIndex(self, server):
         return self.header.explorerClientsBox.findData(server)
 

src/qt/dlg_configureExplorer.py

@@ -5,7 +5,7 @@
 # file LICENSE.txt or http://www.opensource.org/licenses/mit-license.php.
 
 from PyQt5.QtWidgets import QDialog, QHBoxLayout, QVBoxLayout, QLabel, \
-    QListWidget, QFrame, QFormLayout, QComboBox, QLineEdit, QListWidgetItem, \
+    QListWidget, QFrame, QFormLayout, QLineEdit, QListWidgetItem, \
     QWidget, QPushButton, QMessageBox
 
 from misc import myPopUp