diff --git a/smartcard/Card.py b/smartcard/Card.py
index b82fad52..a261c744 100644
--- a/smartcard/Card.py
+++ b/smartcard/Card.py
@@ -21,7 +21,6 @@
 along with pyscard; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 """
-from smartcard.Exceptions import CardConnectionException, NoCardException
 from smartcard.reader.Reader import Reader
 from smartcard.System import readers
 from smartcard.util import toHexString
diff --git a/smartcard/CardConnection.py b/smartcard/CardConnection.py
index 607185e0..15bb52b2 100644
--- a/smartcard/CardConnection.py
+++ b/smartcard/CardConnection.py
@@ -24,8 +24,6 @@
 """
 
 from smartcard.CardConnectionEvent import CardConnectionEvent
-from smartcard.Exceptions import SmartcardException
-from smartcard.Observer import Observer
 from smartcard.Observer import Observable
 
 
diff --git a/smartcard/CardMonitoring.py b/smartcard/CardMonitoring.py
index f3041044..5624456d 100644
--- a/smartcard/CardMonitoring.py
+++ b/smartcard/CardMonitoring.py
@@ -33,12 +33,9 @@
 from time import sleep
 import traceback
 
-from smartcard.System import readers
-from smartcard.Exceptions import CardRequestTimeoutException
 from smartcard.Observer import Observer
 from smartcard.Observer import Observable
 
-from smartcard.CardType import AnyCardType
 from smartcard.CardRequest import CardRequest
 
 _START_ON_DEMAND_ = False
@@ -219,7 +216,6 @@ def __getattr__(self, name):
 
 
 if __name__ == "__main__":
-    from smartcard.CardMonitoring import CardMonitor
     print('insert or remove cards in the next 10 seconds')
 
     # a simple card observer that prints added/removed cards
diff --git a/smartcard/CardService.py b/smartcard/CardService.py
index 36ead64c..feaac9e3 100644
--- a/smartcard/CardService.py
+++ b/smartcard/CardService.py
@@ -31,7 +31,6 @@
 """
 
 from __future__ import print_function
-from smartcard.Exceptions import SmartcardException
 from smartcard.scard import *
 
 
diff --git a/smartcard/CardType.py b/smartcard/CardType.py
index 5b17e2bb..a9d6cdff 100644
--- a/smartcard/CardType.py
+++ b/smartcard/CardType.py
@@ -22,6 +22,7 @@
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 """
 from __future__ import print_function
+from smartcard.Exceptions import InvalidATRMaskLengthException
 from smartcard.System import readers
 from smartcard.util import toHexString
 
diff --git a/smartcard/ClassLoader.py b/smartcard/ClassLoader.py
index 3b232152..3cc59c56 100644
--- a/smartcard/ClassLoader.py
+++ b/smartcard/ClassLoader.py
@@ -9,10 +9,6 @@
 License: PSF license (http://docs.python.org/license.html).
 """
 
-import sys
-import types
-
-
 def get_mod(modulePath):
     """Import a module."""
     return __import__(modulePath, globals(), locals(), [''])
diff --git a/smartcard/Examples/wx/pcscdiag/pcscdiag.py b/smartcard/Examples/wx/pcscdiag/pcscdiag.py
index 697cfd30..7a1dbda0 100755
--- a/smartcard/Examples/wx/pcscdiag/pcscdiag.py
+++ b/smartcard/Examples/wx/pcscdiag/pcscdiag.py
@@ -35,7 +35,7 @@
 # wxPython GUI modules (http://www.wxpython.org)
 try:
     import wx
-except:
+except ImportError:
     print('You need wxpython (http://www.wxpython.org) ' + \
           'to run this sample from the source code!')
     print('press a key to continue')
diff --git a/smartcard/ExclusiveConnectCardConnection.py b/smartcard/ExclusiveConnectCardConnection.py
index 20fcdb1d..7616e895 100644
--- a/smartcard/ExclusiveConnectCardConnection.py
+++ b/smartcard/ExclusiveConnectCardConnection.py
@@ -22,7 +22,6 @@
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 """
 from __future__ import print_function
-from smartcard.CardConnection import CardConnection
 from smartcard.CardConnectionDecorator import CardConnectionDecorator
 from smartcard.Exceptions import CardConnectionException
 from smartcard.scard import SCardConnect, SCardDisconnect
diff --git a/smartcard/ExclusiveTransmitCardConnection.py b/smartcard/ExclusiveTransmitCardConnection.py
index e022290e..1d5b2292 100644
--- a/smartcard/ExclusiveTransmitCardConnection.py
+++ b/smartcard/ExclusiveTransmitCardConnection.py
@@ -22,13 +22,11 @@
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 """
 from __future__ import print_function
-from smartcard.CardConnection import CardConnection
 from smartcard.CardConnectionDecorator import CardConnectionDecorator
 from smartcard.Exceptions import CardConnectionException
 from smartcard.scard import SCardBeginTransaction, SCardEndTransaction
 from smartcard.scard import SCARD_LEAVE_CARD
 from smartcard.scard import SCardGetErrorMessage
-from smartcard.pcsc import PCSCCardConnection
 import smartcard.pcsc
 
 
diff --git a/smartcard/PassThruCardService.py b/smartcard/PassThruCardService.py
index 039d63c4..d7b99948 100644
--- a/smartcard/PassThruCardService.py
+++ b/smartcard/PassThruCardService.py
@@ -54,7 +54,6 @@ def supports(cardname):
     SELECT = [0xA0, 0xA4, 0x00, 0x00, 0x02]
     DF_TELECOM = [0x7F, 0x10]
     from smartcard.System import readers
-    from smartcard.CardConnection import CardConnection
     cc = readers()[0].createConnection()
     cs = PassThruCardService(cc)
     cs.connection.connect()
diff --git a/smartcard/ReaderMonitoring.py b/smartcard/ReaderMonitoring.py
index 10ec1a2a..ac3f5ba4 100644
--- a/smartcard/ReaderMonitoring.py
+++ b/smartcard/ReaderMonitoring.py
@@ -29,12 +29,11 @@
 """
 
 from __future__ import print_function
-from threading import Thread, Event, enumerate
+from threading import Thread, Event
 from time import sleep
 import traceback
 
 import smartcard.System
-from smartcard.Exceptions import ListReadersException
 from smartcard.Observer import Observer
 from smartcard.Observer import Observable
 from smartcard.Synchronization import *
@@ -204,7 +203,6 @@ def stop(self):
         self.join()
 
 if __name__ == "__main__":
-    from smartcard.ReaderMonitoring import ReaderMonitor
     print('insert or remove readers in the next 20 seconds')
 
     # a simple reader observer that prints added/removed readers
diff --git a/smartcard/Session.py b/smartcard/Session.py
index e67a3e9c..940b10cd 100644
--- a/smartcard/Session.py
+++ b/smartcard/Session.py
@@ -25,7 +25,6 @@
 
 from __future__ import print_function
 from smartcard.Exceptions import InvalidReaderException, NoReadersException
-from smartcard.CardConnection import CardConnection
 from smartcard.PassThruCardService import PassThruCardService
 from smartcard.System import readers
 
diff --git a/smartcard/pcsc/PCSCCardConnection.py b/smartcard/pcsc/PCSCCardConnection.py
index cccc4d35..a3bd7a05 100644
--- a/smartcard/pcsc/PCSCCardConnection.py
+++ b/smartcard/pcsc/PCSCCardConnection.py
@@ -26,7 +26,6 @@
 from smartcard.CardConnection import CardConnection
 from smartcard.Exceptions import (CardConnectionException,
     NoCardException, SmartcardException)
-from smartcard.Observer import Observable
 
 from smartcard.scard import *
 
diff --git a/smartcard/pyro/PyroReader.py b/smartcard/pyro/PyroReader.py
index bbf1bf64..35e0c11f 100644
--- a/smartcard/pyro/PyroReader.py
+++ b/smartcard/pyro/PyroReader.py
@@ -26,9 +26,8 @@
 import Pyro.core
 import Pyro.naming
 
-from smartcard.Exceptions import CardConnectionException, NoCardException
+from smartcard.Exceptions import NoCardException
 from smartcard.reader.Reader import Reader
-from smartcard.reader.ReaderFactory import ReaderFactory
 
 
 class PyroReader(Reader):
diff --git a/smartcard/pyro/server/PyroEventServer.py b/smartcard/pyro/server/PyroEventServer.py
index 3c762f9f..7d284e64 100644
--- a/smartcard/pyro/server/PyroEventServer.py
+++ b/smartcard/pyro/server/PyroEventServer.py
@@ -93,7 +93,6 @@ def __call__(self, signame, sf):
 
 
 if __name__ == '__main__':
-    import sys
     from smartcard.pyro.server.PyroNameServer import PyroNameServer
     pn = PyroNameServer(sys.argv[1:])
     pn.start()
diff --git a/smartcard/pyro/server/RemoteCardConnection.py b/smartcard/pyro/server/RemoteCardConnection.py
index 9df373ee..2b092b7c 100644
--- a/smartcard/pyro/server/RemoteCardConnection.py
+++ b/smartcard/pyro/server/RemoteCardConnection.py
@@ -26,10 +26,7 @@
 import Pyro.core
 import Pyro.naming
 
-from smartcard.CardConnection import CardConnection
 from smartcard.CardConnectionDecorator import CardConnectionDecorator
-from smartcard.Exceptions import CardConnectionException, NoCardException
-from smartcard.Observer import Observable
 
 
 class RemoteCardConnection(CardConnectionDecorator, Pyro.core.ObjBase):
diff --git a/smartcard/pyro/server/RemoteReaderServer.py b/smartcard/pyro/server/RemoteReaderServer.py
index 4680eb98..5e5157a8 100644
--- a/smartcard/pyro/server/RemoteReaderServer.py
+++ b/smartcard/pyro/server/RemoteReaderServer.py
@@ -28,16 +28,12 @@
 try:
     import Pyro.core
     import Pyro.naming
-except:
+except ImportError:
     print('You need pyro (python remote objects) ' + \
           'at http://www.xs4all.nl/~irmen/pyro3/')
     import sys
     sys.exit()
 
-import signal
-import time
-
-import smartcard.System
 from smartcard.reader.Reader import Reader
 from smartcard.ReaderMonitoring import ReaderMonitor, ReaderObserver
 from smartcard.pyro.server.RemoteCardConnection import RemoteCardConnection
diff --git a/smartcard/wx/SimpleSCardAppFrame.py b/smartcard/wx/SimpleSCardAppFrame.py
index c5e450ab..f08d120f 100644
--- a/smartcard/wx/SimpleSCardAppFrame.py
+++ b/smartcard/wx/SimpleSCardAppFrame.py
@@ -26,10 +26,11 @@
 
 import os.path
 import wx
+
 import smartcard.wx
-import APDUTracerPanel
-import CardAndReaderTreePanel
-import ReaderToolbar
+from smartcard.wx import APDUTracerPanel
+from smartcard.wx import CardAndReaderTreePanel
+from smartcard.wx import ReaderToolbar
 
 import smartcard
 from smartcard.wx.SimpleSCardAppEventObserver import \