Check for None with is rather than ==

djangoapps/courseware/capa/capa_problem.py

@@ -91,7 +91,7 @@ class LoncapaProblem(object):
         self.problem_id = id
         self.system = system
 
-        if seed != None:
+        if seed is not None:
             self.seed = seed
 
         if state:

djangoapps/courseware/capa/inputtypes.py

@@ -133,7 +133,7 @@ class SimpleInput():# XModule
 
 
 def register_render_function(fn, names=None, cls=SimpleInput):
-    if names == None:
+    if names is None:
         SimpleInput.xml_tags[fn.__name__] = fn
     else:
         raise NotImplementedError

djangoapps/courseware/capa/responsetypes.py

@@ -109,7 +109,7 @@ class MultipleChoiceResponse(GenericResponse):
             if rtype not in ["MultipleChoice"]:
                 response.set("type", "MultipleChoice")		# force choicegroup to be MultipleChoice if not valid
             for choice in list(response):
-                if choice.get("name") == None:
+                if choice.get("name") is None:
                     choice.set("name", "choice_"+str(i))
                     i+=1
                 else:
@@ -121,7 +121,7 @@ class TrueFalseResponse(MultipleChoiceResponse):
         for response in self.xml.xpath("choicegroup"):
             response.set("type", "TrueFalse")
             for choice in list(response):
-                if choice.get("name") == None:
+                if choice.get("name") is None:
                     choice.set("name", "choice_"+str(i))
                     i+=1
                 else:
@@ -292,7 +292,7 @@ def sympy_check2():
                 self.code = ''
             else:
                 answer_src = answer.get('src')
-                if answer_src != None:
+                if answer_src is not None:
                     self.code = open(settings.DATA_DIR+'src/'+answer_src).read()
                 else:
                     self.code = answer.text
@@ -418,7 +418,7 @@ class ExternalResponse(GenericResponse):
                            id=xml.get('id'))[0]
 
         answer_src = answer.get('src')
-        if answer_src != None:
+        if answer_src is not None:
             self.code = open(settings.DATA_DIR+'src/'+answer_src).read()
         else:
             self.code = answer.text
@@ -489,7 +489,7 @@ class FormulaResponse(GenericResponse):
 
         self.context = context
         ts = xml.get('type')
-        if ts == None:
+        if ts is None:
             typeslist = []
         else:
             typeslist = ts.split(',')
@@ -558,7 +558,7 @@ class SchematicResponse(GenericResponse):
         answer = xml.xpath('//*[@id=$id]//answer',
                            id=xml.get('id'))[0]
         answer_src = answer.get('src')
-        if answer_src != None:
+        if answer_src is not None:
             self.code = self.system.filestore.open('src/'+answer_src).read() # Untested; never used
         else:
             self.code = answer.text

djangoapps/courseware/content_parser.py

@@ -126,7 +126,7 @@ def propogate_downward_tag(element, attribute_name, parent_attribute = None):
     child (A) already has that attribute, A will keep the same attribute and
     all of A's children will inherit A's attribute. This is a recursive call.'''
     
-    if (parent_attribute == None): #This is the entry call. Select all elements with this attribute
+    if (parent_attribute is None): #This is the entry call. Select all elements with this attribute
         all_attributed_elements = element.xpath("//*[@" + attribute_name +"]")
         for attributed_element in all_attributed_elements:
             attribute_value = attributed_element.get(attribute_name)

djangoapps/courseware/grades.py

@@ -190,7 +190,7 @@ def get_score(user, problem, cache, coursename=None):
             correct=float(response.grade)
         
     # Grab max grade from cache, or if it doesn't exist, compute and save to DB
-    if id in cache and response.max_grade != None:
+    if id in cache and response.max_grade is not None:
         total = response.max_grade
     else:
         ## HACK 1: We shouldn't specifically reference capa_module

djangoapps/courseware/module_render.py

@@ -75,7 +75,7 @@ def grade_histogram(module_id):
 
     grades = list(cursor.fetchall())
     grades.sort(key=lambda x:x[0]) # Probably not necessary
-    if (len(grades) == 1 and grades[0][0] == None):
+    if (len(grades) == 1 and grades[0][0] is None):
         return []
     return grades
 

djangoapps/courseware/modules/capa_module.py

@@ -97,7 +97,7 @@ class Module(XModule):
             reset_button = False
 
         # We don't need a "save" button if infinite number of attempts and non-randomized
-        if self.max_attempts == None and self.rerandomize != "always":
+        if self.max_attempts is None and self.rerandomize != "always":
             save_button = False
 
         # Check if explanation is available, and if so, give a link
@@ -222,7 +222,7 @@ class Module(XModule):
         ''' Is the student still allowed to submit answers? '''
         if self.attempts == self.max_attempts:
             return True
-        if self.close_date != None and datetime.datetime.utcnow() > self.close_date:
+        if self.close_date is not None and datetime.datetime.utcnow() > self.close_date:
             return True
 
         return False

djangoapps/courseware/modules/seq_module.py

@@ -51,7 +51,7 @@ class Module(XModule):
         ## Returns a set of all types of all sub-children
         child_classes = [set([i.tag for i in e.iter()]) for e in self.xmltree]
 
-        titles = ["\n".join([i.get("name").strip() for i in e.iter() if i.get("name") != None]) \
+        titles = ["\n".join([i.get("name").strip() for i in e.iter() if i.get("name") is not None]) \
                        for e in self.xmltree]
 
         self.contents = [j(self.render_function(e)) for e in self.xmltree]
@@ -91,7 +91,7 @@ class Module(XModule):
 
         self.position = 1
 
-        if state != None:
+        if state is not None:
             state = json.loads(state)
             if 'position' in state: self.position = int(state['position'])
 

djangoapps/courseware/modules/video_module.py

@@ -47,7 +47,7 @@ class Module(XModule):
         self.youtube = xmltree.get('youtube')
         self.name = xmltree.get('name')
         self.position = 0
-        if state != None:
+        if state is not None:
             state = json.loads(state)
             if 'position' in state:
                 self.position = int(float(state['position']))

djangoapps/courseware/views.py

@@ -57,7 +57,7 @@ def profile(request, student_id = None):
     ''' User profile. Show username, location, etc, as well as grades .
         We need to allow the user to change some of these settings .'''
 
-    if student_id == None:
+    if student_id is None:
         student = request.user
     else: 
         if 'course_admin' not in content_parser.user_groups(request.user):
@@ -194,7 +194,7 @@ def index(request, course=None, chapter="Using the System", section="Hints"):
     else:
         module_wrapper = dom_module[0]
 
-    if module_wrapper == None:
+    if module_wrapper is None:
         module = None
     elif module_wrapper.get("src"):
         module = content_parser.section_file(user=user, section=module_wrapper.get("src"), coursename=course)

djangoapps/simplewiki/views.py

@@ -482,7 +482,7 @@ def check_permissions(request, article, check_read=False, check_write=False, che
     
     locked_err = check_locked and article.locked
     
-    if revision == None:
+    if revision is None:
         revision = article.current_revision
     deleted_err = check_deleted and not (revision.deleted == 0)
     if (request.user.is_superuser):

templates/video.html

-% if name is not UNDEFINED and name != None:
+% if name is not UNDEFINED and name is not None:
   <h1> ${name} </h1>
 % endif