Test for object identity when checking for None in Python

Consistently use "is" or "is not" to compare variables to None,
because doing so is preferrable, as per PEP 8
(http://www.python.org/dev/peps/pep-0008/#programming-recommendations):

> Comparisons to singletons like None should always be done with is or
> is not, never the equality operators.

generator.py

@@ -136,7 +136,7 @@ class docParser(xml.sax.handler.ContentHandler):
             print "end %s" % tag
         if tag == 'function':
             # fuctions come from source files, hence 'virerror.c'
-            if self.function != None:
+            if self.function is not None:
                 if (self.function_module == "libvirt" or
                     self.function_module == "virevent" or
                     self.function_module == "virerror"):
@@ -641,9 +641,9 @@ def print_function_wrapper(module, name, output, export, include):
             (f, t, n, c) = py_types[arg[1]]
             if (f == 'z') and (name in foreign_encoding_args) and (num_bufs == 0):
                 f = 't#'
-            if f != None:
+            if f is not None:
                 format = format + f
-            if t != None:
+            if t is not None:
                 format_args = format_args + ", &pyobj_%s" % (arg[0])
                 c_args = c_args + "    PyObject *pyobj_%s;\n" % (arg[0])
                 c_convert = c_convert + \
@@ -686,7 +686,7 @@ def print_function_wrapper(module, name, output, export, include):
     elif py_types.has_key(ret[0]):
         (f, t, n, c) = py_types[ret[0]]
         c_return = "    %s c_retval;\n" % (ret[0])
-        if file == "python_accessor" and ret[2] != None:
+        if file == "python_accessor" and ret[2] is not None:
             c_call = "\n    c_retval = %s->%s;\n" % (args[0][0], ret[2])
         else:
             c_call = "\n    c_retval = %s(%s);\n" % (name, c_call)
@@ -708,7 +708,7 @@ def print_function_wrapper(module, name, output, export, include):
             unknown_types[ret[0]] = [name]
         return -1
 
-    if cond != None and cond != "":
+    if cond is not None and cond != "":
         include.write("#if %s\n" % cond)
         export.write("#if %s\n" % cond)
         output.write("#if %s\n" % cond)
@@ -729,14 +729,14 @@ def print_function_wrapper(module, name, output, export, include):
 
     if file == "python":
         # Those have been manually generated
-        if cond != None and cond != "":
+        if cond is not None and cond != "":
             include.write("#endif\n")
             export.write("#endif\n")
             output.write("#endif\n")
         return 1
     if file == "python_accessor" and ret[0] != "void" and ret[2] is None:
         # Those have been manually generated
-        if cond != None and cond != "":
+        if cond is not None and cond != "":
             include.write("#endif\n")
             export.write("#endif\n")
             output.write("#endif\n")
@@ -771,7 +771,7 @@ def print_function_wrapper(module, name, output, export, include):
     output.write("    LIBVIRT_END_ALLOW_THREADS;\n")
     output.write(ret_convert)
     output.write("}\n\n")
-    if cond != None and cond != "":
+    if cond is not None and cond != "":
         include.write("#endif /* %s */\n" % cond)
         export.write("#endif /* %s */\n" % cond)
         output.write("#endif /* %s */\n" % cond)
@@ -1313,7 +1313,7 @@ def buildWrappers(module):
     classes.write("#\n")
     classes.write("# WARNING WARNING WARNING WARNING\n")
     classes.write("#\n")
-    if extra != None:
+    if extra is not None:
         classes.writelines(extra.readlines())
     classes.write("#\n")
     classes.write("# WARNING WARNING WARNING WARNING\n")
@@ -1321,7 +1321,7 @@ def buildWrappers(module):
     classes.write("# Automatically written part of python bindings for libvirt\n")
     classes.write("#\n")
     classes.write("# WARNING WARNING WARNING WARNING\n")
-    if extra != None:
+    if extra is not None:
         extra.close()
 
     if function_classes.has_key("None"):
@@ -1460,7 +1460,7 @@ def buildWrappers(module):
             destruct=None
             if classes_destructors.has_key(classname):
                 classes.write("    def __del__(self):\n")
-                classes.write("        if self._o != None:\n")
+                classes.write("        if self._o is not None:\n")
                 classes.write("            libvirtmod.%s(self._o)\n" %
                               classes_destructors[classname])
                 classes.write("        self._o = None\n\n")
@@ -1776,7 +1776,7 @@ def qemuBuildWrappers(module):
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
     fd.write("#\n")
-    if extra != None:
+    if extra is not None:
         fd.writelines(extra.readlines())
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
@@ -1784,7 +1784,7 @@ def qemuBuildWrappers(module):
     fd.write("# Automatically written part of python bindings for libvirt\n")
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
-    if extra != None:
+    if extra is not None:
         extra.close()
 
     fd.write("try:\n")
@@ -1888,7 +1888,7 @@ def lxcBuildWrappers(module):
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
     fd.write("#\n")
-    if extra != None:
+    if extra is not None:
         fd.writelines(extra.readlines())
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
@@ -1896,7 +1896,7 @@ def lxcBuildWrappers(module):
     fd.write("# Automatically written part of python bindings for libvirt\n")
     fd.write("#\n")
     fd.write("# WARNING WARNING WARNING WARNING\n")
-    if extra != None:
+    if extra is not None:
         extra.close()
 
     fd.write("try:\n")

libvirt-override-virConnect.py

@@ -7,7 +7,7 @@
         except AttributeError:
            pass
 
-        if self._o != None:
+        if self._o is not None:
             libvirtmod.virConnectClose(self._o)
         self._o = None
 

libvirt-override-virStream.py

@@ -5,7 +5,7 @@
         except AttributeError:
            pass
 
-        if self._o != None:
+        if self._o is not None:
             libvirtmod.virStreamFree(self._o)
         self._o = None
 
@@ -103,7 +103,7 @@
         the request would block, integer -2 is returned.
         """
         ret = libvirtmod.virStreamRecv(self._o, nbytes)
-        if ret == None: raise libvirtError ('virStreamRecv() failed')
+        if ret is None: raise libvirtError ('virStreamRecv() failed')
         return ret
 
     def send(self, data):