some bugs are fixed.

	modified:   persepolis/scripts/download.py
	modified:   persepolis/scripts/mainwindow.py
	modified:   persepolis/scripts/progress.py
	modified:   persepolis/scripts/shutdown.py

persepolis/scripts/download.py

@@ -320,15 +320,13 @@ def downloadAria(gid, parent):
             error_message = str(traceback.format_exc())
             logger.sendToLog(error_message, "ERROR")
 
-            # return None!
-            return None
+            # return False!
+            return False
     else:
         # if start_time_status is "stopped" it means download Canceled by user
         logger.sendToLog("Download Canceled", "INFO")
 
 # this function returns list of download information
-
-
 def tellActive():
     # get download information from aria2
     try:

persepolis/scripts/mainwindow.py

@@ -475,7 +475,7 @@ def run(self):
         # if request is not successful then persepolis is checking rpc
         # connection with download.aria2Version() function
         answer = download.downloadAria(self.gid, self.parent)
-        if not(answer):
+        if answer == False:
             version_answer = download.aria2Version()
 
             if version_answer == 'did not respond':

persepolis/scripts/progress.py

@@ -20,14 +20,14 @@
 from persepolis.scripts.shutdown import shutDown
 from persepolis.scripts.bubble import notifySend
 from persepolis.scripts import download
+from persepolis.constants import OS
 from PyQt5.QtGui import QIcon
 import subprocess
 import platform
 import time
 
 os_type = platform.system()
 
-
 class ShutDownThread(QThread):
     def __init__(self, parent, gid, password=None):
         QThread.__init__(self)

persepolis/scripts/shutdown.py

@@ -19,10 +19,8 @@
 import subprocess
 import platform
 
-# find os platform
 os_type = platform.system()
 
-
 def shutDown(parent, gid=None, category=None, password=None):
     # for queue >> gid = None
     # for single downloads >> category = None