Use 'is' to compare with None

Issues were detected by PyCharm Community Edition 3.4.

IPython/lib/display.py

@@ -450,7 +450,7 b' class FileLinks(FileLink):'
             display_fnames = []
             for fname in fnames:
                 if (isfile(join(dirname,fname)) and
-                       (included_suffixes == None or
+                       (included_suffixes is None or
                         splitext(fname)[1] in included_suffixes)):
                       display_fnames.append(fname)
 

IPython/qt/console/magic_helper.py

@@ -116,7 +116,7 b' class MagicHelper(QtGui.QDockWidget):'
            instance is expected to invoke populate_magic_helper() when magic
            info is available.
         """
-        if not visible or self.data != None:
+        if not visible or self.data is not None:
             return
         self.data = {}
         self.search_class.clear()
@@ -178,14 +178,14 b' class MagicHelper(QtGui.QDockWidget):'
         """Emit pasteRequested signal with currently selected item text
         """
         text = self._get_current_search_item(item)
-        if text != None:
+        if text is not None:
             self.pasteRequested.emit(text)
 
     def run_requested(self, item = None):
         """Emit runRequested signal with currently selected item text
         """
         text = self._get_current_search_item(item)
-        if text != None:            
+        if text is not None:
             self.runRequested.emit(text)
 
     def filter_magic_helper(self, regex, cls):
@@ -193,9 +193,9 b' class MagicHelper(QtGui.QDockWidget):'
            regex and class match cls.
            If cls equals 'any' - any class matches.
         """
-        if regex == "" or regex == None:
+        if regex == "" or regex is None:
             regex = '.'
-        if cls == None:
+        if cls is None:
             cls = 'any'
 
         self.search_list.clear()

IPython/qt/console/mainwindow.py

@@ -144,7 +144,7 b' class MainWindow(QtGui.QMainWindow):'
         # of this is when 'exit' is sent in a slave tab. 'exit' will be
         # re-sent by this function on the master widget, which ask all slave
         # widgets to exit
-        if closing_widget==None:
+        if closing_widget is None:
             return
 
         #get a list of all slave widgets on the same kernel.
@@ -719,12 +719,12 b' class MainWindow(QtGui.QMainWindow):'
         QtCore.QTimer.singleShot(200, self.active_frontend._control.setFocus)
 
     def magic_helper_paste_requested(self, text = None):
-        if text != None:
+        if text is not None:
             self.active_frontend.input_buffer = text            
             self._set_active_frontend_focus()
 
     def magic_helper_run_requested(self, text = None):
-        if text != None:            
+        if text is not None:
             self.active_frontend.execute(text)  
             self._set_active_frontend_focus()
 

IPython/utils/_process_win32_controller.py

@@ -296,7 +296,7 b' class Win32ShellCommandController(object):'
             c_hstdin = None
             CloseHandle(c_hstdout)
             c_hstdout = None
-            if c_hstderr != None:
+            if c_hstderr is not None:
                 CloseHandle(c_hstderr)
                 c_hstderr = None
 
@@ -403,10 +403,10 b' class Win32ShellCommandController(object):'
         These functions are called from different threads (but not
         concurrently, because of the GIL).
         """
-        if stdout_func == None and stdin_func == None and stderr_func == None:
+        if stdout_func is None and stdin_func is None and stderr_func is None:
             return self._run_stdio()
 
-        if stderr_func != None and self.mergeout:
+        if stderr_func is not None and self.mergeout:
             raise RuntimeError("Shell command was initiated with "
                     "merged stdin/stdout, but a separate stderr_func "
                     "was provided to the run() method")
@@ -421,7 +421,7 b' class Win32ShellCommandController(object):'
         threads.append(threading.Thread(target=self._stdout_thread,
                                     args=(self.hstdout, stdout_func)))
         if not self.mergeout:
-            if stderr_func == None:
+            if stderr_func is None:
                 stderr_func = stdout_func
             threads.append(threading.Thread(target=self._stdout_thread,
                                         args=(self.hstderr, stderr_func)))
@@ -541,7 +541,7 b' class Win32ShellCommandController(object):'
         if self.hstderr:
             CloseHandle(self.hstderr)
             self.hstderr = None
-        if self.piProcInfo != None:
+        if self.piProcInfo is not None:
             CloseHandle(self.piProcInfo.hProcess)
             CloseHandle(self.piProcInfo.hThread)
             self.piProcInfo = None