diff --git a/cms/djangoapps/contentstore/views/course.py b/cms/djangoapps/contentstore/views/course.py
index 36ef38475f..ddf605eb96 100644
--- a/cms/djangoapps/contentstore/views/course.py
+++ b/cms/djangoapps/contentstore/views/course.py
@@ -21,7 +21,7 @@ from xmodule.modulestore.django import modulestore
 from xmodule.contentstore.content import StaticContent
 from xmodule.tabs import PDFTextbookTabs
 
-from xmodule.modulestore.exceptions import ItemNotFoundError, InvalidLocationError, InsufficientSpecificationError
+from xmodule.modulestore.exceptions import ItemNotFoundError, InvalidLocationError
 from opaque_keys import InvalidKeyError
 from xmodule.modulestore.locations import Location, SlashSeparatedCourseKey
 
diff --git a/cms/djangoapps/contentstore/views/import_export.py b/cms/djangoapps/contentstore/views/import_export.py
index e583c7230a..ffc161c4b4 100644
--- a/cms/djangoapps/contentstore/views/import_export.py
+++ b/cms/djangoapps/contentstore/views/import_export.py
@@ -30,7 +30,6 @@ from xmodule.modulestore.xml_exporter import export_to_xml
 
 from .access import has_course_access
 
-from .access import has_course_access
 from extract_tar import safetar_extractall
 from student import auth
 from student.roles import CourseInstructorRole, CourseStaffRole, GlobalStaff
diff --git a/common/djangoapps/student/management/commands/anonymized_id_mapping.py b/common/djangoapps/student/management/commands/anonymized_id_mapping.py
index 6552d88db2..363c3e74be 100644
--- a/common/djangoapps/student/management/commands/anonymized_id_mapping.py
+++ b/common/djangoapps/student/management/commands/anonymized_id_mapping.py
@@ -13,7 +13,6 @@ import csv
 from django.contrib.auth.models import User
 from django.core.management.base import BaseCommand, CommandError
 
-from opaque_keys import InvalidKeyError
 from student.models import anonymous_id_for_user
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
 
diff --git a/common/djangoapps/student/management/commands/create_random_users.py b/common/djangoapps/student/management/commands/create_random_users.py
index 465077afec..000ebd2ac1 100644
--- a/common/djangoapps/student/management/commands/create_random_users.py
+++ b/common/djangoapps/student/management/commands/create_random_users.py
@@ -1,16 +1,18 @@
-##
-## A script to create some dummy users
-
+"""
+A script to create some dummy users
+"""
 from django.core.management.base import BaseCommand
 from student.models import CourseEnrollment
-
+from opaque_keys import InvalidKeyError
+from xmodule.modulestore.keys import CourseKey
+from xmodule.modulestore.locations import SlashSeparatedCourseKey
 from student.views import _do_create_account, get_random_post_override
 
 
-def create(n, course_key):
-    """Create n users, enrolling them in course_key if it's not None"""
-    for i in range(n):
-        (user, user_profile, _) = _do_create_account(get_random_post_override())
+def create(num, course_key):
+    """Create num users, enrolling them in course_key if it's not None"""
+    for idx in range(num):
+        (user, user_profile, __) = _do_create_account(get_random_post_override())
         if course_key is not None:
             CourseEnrollment.enroll(user, course_key)
 
@@ -31,7 +33,7 @@ Examples:
             print Command.help
             return
 
-        n = int(args[0])
+        num = int(args[0])
 
         if len(args) == 2:
             try:
@@ -41,4 +43,4 @@ Examples:
         else:
             course_key = None
 
-        create(n, course_key)
+        create(num, course_key)
diff --git a/common/djangoapps/student/management/commands/get_grades.py b/common/djangoapps/student/management/commands/get_grades.py
index bbbbd3453d..a3857e8e9e 100644
--- a/common/djangoapps/student/management/commands/get_grades.py
+++ b/common/djangoapps/student/management/commands/get_grades.py
@@ -1,3 +1,7 @@
+"""
+Management command to generate a list of grades for
+all students that are enrolled in a course.
+"""
 from courseware import grades, courses
 from certificates.models import GeneratedCertificate
 from django.test.client import RequestFactory
diff --git a/common/djangoapps/student/roles.py b/common/djangoapps/student/roles.py
index cd69ed385d..89043b2c3a 100644
--- a/common/djangoapps/student/roles.py
+++ b/common/djangoapps/student/roles.py
@@ -7,7 +7,6 @@ from abc import ABCMeta, abstractmethod
 
 from django.contrib.auth.models import User
 from student.models import CourseAccessRole
-from xmodule_django.models import CourseKeyField
 
 
 class AccessRole(object):
diff --git a/common/lib/xmodule/xmodule/modulestore/loc_mapper_store.py b/common/lib/xmodule/xmodule/modulestore/loc_mapper_store.py
index 0f04298685..69405c2e65 100644
--- a/common/lib/xmodule/xmodule/modulestore/loc_mapper_store.py
+++ b/common/lib/xmodule/xmodule/modulestore/loc_mapper_store.py
@@ -10,7 +10,6 @@ import urllib
 from xmodule.modulestore.exceptions import InvalidLocationError, ItemNotFoundError
 from xmodule.modulestore.locator import BlockUsageLocator, CourseLocator
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
-from xmodule.modulestore.keys import UsageKey
 
 
 class LocMapperStore(object):
diff --git a/lms/djangoapps/bulk_email/forms.py b/lms/djangoapps/bulk_email/forms.py
index f62d28e03b..43fda78fe9 100644
--- a/lms/djangoapps/bulk_email/forms.py
+++ b/lms/djangoapps/bulk_email/forms.py
@@ -11,7 +11,6 @@ from bulk_email.models import CourseEmailTemplate, COURSE_EMAIL_MESSAGE_BODY_TAG
 from opaque_keys import InvalidKeyError
 from xmodule.modulestore import XML_MODULESTORE_TYPE
 from xmodule.modulestore.django import modulestore
-from opaque_keys import InvalidKeyError
 from xmodule.modulestore.keys import CourseKey
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
 
diff --git a/lms/djangoapps/certificates/management/commands/cert_whitelist.py b/lms/djangoapps/certificates/management/commands/cert_whitelist.py
index 0aa7d81ab7..a11d0c27d6 100644
--- a/lms/djangoapps/certificates/management/commands/cert_whitelist.py
+++ b/lms/djangoapps/certificates/management/commands/cert_whitelist.py
@@ -1,3 +1,7 @@
+"""
+Management command which sets or gets the certificate whitelist for a given
+user/course
+"""
 from django.core.management.base import BaseCommand, CommandError
 from optparse import make_option
 from opaque_keys import InvalidKeyError
@@ -56,7 +60,7 @@ class Command(BaseCommand):
         try:
             course = CourseKey.from_string(course_id)
         except InvalidKeyError:
-            log.warning("Course id %s could not be parsed as a CourseKey; falling back to SSCK.from_dep_str", course_id)
+            print("Course id {} could not be parsed as a CourseKey; falling back to SSCK.from_dep_str".format(course_id))
             course = SlashSeparatedCourseKey.from_deprecated_string(course_id)
 
         if options['add'] and options['del']:
diff --git a/lms/djangoapps/certificates/management/commands/ungenerated_certs.py b/lms/djangoapps/certificates/management/commands/ungenerated_certs.py
index 0a86c102c2..81c3e47f43 100644
--- a/lms/djangoapps/certificates/management/commands/ungenerated_certs.py
+++ b/lms/djangoapps/certificates/management/commands/ungenerated_certs.py
@@ -1,3 +1,7 @@
+"""
+Management command to find all students that need certificates for
+courses that have finished, and put their cert requests on the queue.
+"""
 from django.core.management.base import BaseCommand, CommandError
 from certificates.models import certificate_status_for_student
 from certificates.queue import XQueueCertInterface
@@ -73,7 +77,7 @@ class Command(BaseCommand):
             try:
                 course = CourseKey.from_string(options['course'])
             except InvalidKeyError:
-                log.warning("Course id %s could not be parsed as a CourseKey; falling back to SSCK.from_dep_str", course_id)
+                print("Course id {} could not be parsed as a CourseKey; falling back to SSCK.from_dep_str".format(options['course']))
                 course = SlashSeparatedCourseKey.from_deprecated_string(options['course'])
             ended_courses = [course]
         else:
diff --git a/lms/djangoapps/courseware/models.py b/lms/djangoapps/courseware/models.py
index 2007046e33..cb471dd79c 100644
--- a/lms/djangoapps/courseware/models.py
+++ b/lms/djangoapps/courseware/models.py
@@ -113,7 +113,12 @@ class StudentModuleHistory(models.Model):
     max_grade = models.FloatField(null=True, blank=True)
 
     @receiver(post_save, sender=StudentModule)
-    def save_history(sender, instance, **kwargs):  # pylint: disable=no-self-argument
+    def save_history(sender, instance, **kwargs):  # pylint: disable=no-self-argument, unused-argument
+        """
+        Checks the instance's module_type, and creates & saves a
+        StudentModuleHistory entry if the module_type is one that
+        we save.
+        """
         if instance.module_type in StudentModuleHistory.HISTORY_SAVING_TYPES:
             history_entry = StudentModuleHistory(student_module=instance,
                                                  version=None,
diff --git a/lms/djangoapps/courseware/tests/test_video_handlers.py b/lms/djangoapps/courseware/tests/test_video_handlers.py
index 75aaa516f7..4e332c91a8 100644
--- a/lms/djangoapps/courseware/tests/test_video_handlers.py
+++ b/lms/djangoapps/courseware/tests/test_video_handlers.py
@@ -22,7 +22,6 @@ from xmodule.video_module.transcripts_utils import (
     TranscriptException,
     TranscriptsGenerationException,
 )
-from xmodule.modulestore.mongo.base import MongoModuleStore
 from xmodule.modulestore.locations import AssetLocation
 
 SRT_content = textwrap.dedent("""
diff --git a/lms/djangoapps/courseware/views.py b/lms/djangoapps/courseware/views.py
index 5fc16f7bb7..c7df0ca3fc 100644
--- a/lms/djangoapps/courseware/views.py
+++ b/lms/djangoapps/courseware/views.py
@@ -47,7 +47,6 @@ from opaque_keys import InvalidKeyError
 
 from microsite_configuration import microsite
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
-from xmodule.modulestore.keys import UsageKey
 
 log = logging.getLogger("edx.courseware")
 
diff --git a/lms/djangoapps/django_comment_client/management/commands/seed_permissions_roles.py b/lms/djangoapps/django_comment_client/management/commands/seed_permissions_roles.py
index 92a82e7946..3650aab05c 100644
--- a/lms/djangoapps/django_comment_client/management/commands/seed_permissions_roles.py
+++ b/lms/djangoapps/django_comment_client/management/commands/seed_permissions_roles.py
@@ -1,3 +1,6 @@
+"""
+Management command to seed default permissions and roles.
+"""
 from django.core.management.base import BaseCommand, CommandError
 from django_comment_common.utils import seed_permissions_roles
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
diff --git a/lms/djangoapps/instructor/management/commands/compute_grades.py b/lms/djangoapps/instructor/management/commands/compute_grades.py
index 41289f1a61..8479474872 100644
--- a/lms/djangoapps/instructor/management/commands/compute_grades.py
+++ b/lms/djangoapps/instructor/management/commands/compute_grades.py
@@ -1,8 +1,8 @@
 #!/usr/bin/python
-#
-# django management command: dump grades to csv files
-# for use by batch processes
-
+"""
+django management command: dump grades to csv files
+for use by batch processes
+"""
 from instructor.offline_gradecalc import offline_grade_calculation
 from courseware.courses import get_course_by_id
 from xmodule.modulestore.django import modulestore
@@ -37,7 +37,7 @@ class Command(BaseCommand):
         except InvalidKeyError:
             course_key = SlashSeparatedCourseKey.from_deprecated_string(course_id)
         try:
-            course = get_course_by_id(course_key)
+            _course = get_course_by_id(course_key)
         except Exception as err:
             print "-----------------------------------------------------------------------------"
             print "Sorry, cannot find course with id {}".format(course_id)
diff --git a/lms/djangoapps/instructor/management/commands/dump_grades.py b/lms/djangoapps/instructor/management/commands/dump_grades.py
index 7312de05a6..a2a68fb21a 100644
--- a/lms/djangoapps/instructor/management/commands/dump_grades.py
+++ b/lms/djangoapps/instructor/management/commands/dump_grades.py
@@ -1,8 +1,8 @@
 #!/usr/bin/python
-#
-# django management command: dump grades to csv files
-# for use by batch processes
-
+"""
+django management command: dump grades to csv files
+for use by batch processes
+"""
 import csv
 
 from instructor.views.legacy import get_student_grade_summary_data
@@ -52,7 +52,9 @@ class Command(BaseCommand):
 
         try:
             course = get_course_by_id(course_key)
-        except Exception as err:
+        # Ok with catching general exception here because this is run as a management command
+        # and the exception is exposed right away to the user.
+        except Exception as err:  # pylint: disable=broad-except
             print "-----------------------------------------------------------------------------"
             print "Sorry, cannot find course with id {}".format(course_id)
             print "Got exception {}".format(err)
diff --git a/lms/djangoapps/instructor/management/commands/openended_post.py b/lms/djangoapps/instructor/management/commands/openended_post.py
index a2a28ee07a..b3e6251cca 100644
--- a/lms/djangoapps/instructor/management/commands/openended_post.py
+++ b/lms/djangoapps/instructor/management/commands/openended_post.py
@@ -6,7 +6,6 @@ from django.core.management.base import BaseCommand
 from optparse import make_option
 
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore.keys import UsageKey
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
 from xmodule.open_ended_grading_classes.openendedchild import OpenEndedChild
 from xmodule.open_ended_grading_classes.open_ended_module import OpenEndedModule
diff --git a/lms/djangoapps/instructor/management/commands/openended_stats.py b/lms/djangoapps/instructor/management/commands/openended_stats.py
index 0ff3157b74..fef4fe73e4 100644
--- a/lms/djangoapps/instructor/management/commands/openended_stats.py
+++ b/lms/djangoapps/instructor/management/commands/openended_stats.py
@@ -9,7 +9,6 @@ from optparse import make_option
 
 from xmodule.modulestore import Location
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore.keys import UsageKey
 from xmodule.modulestore.locations import SlashSeparatedCourseKey
 from xmodule.open_ended_grading_classes.openendedchild import OpenEndedChild
 
diff --git a/lms/djangoapps/instructor/offline_gradecalc.py b/lms/djangoapps/instructor/offline_gradecalc.py
index 02b46534e4..9c77bc276e 100644
--- a/lms/djangoapps/instructor/offline_gradecalc.py
+++ b/lms/djangoapps/instructor/offline_gradecalc.py
@@ -1,10 +1,11 @@
-# ======== Offline calculation of grades =============================================================================
-#
-# Computing grades of a large number of students can take a long time.  These routines allow grades to
-# be computed offline, by a batch process (eg cronjob).
-#
-# The grades are stored in the OfflineComputedGrade table of the courseware model.
+"""
+======== Offline calculation of grades =============================================================
 
+Computing grades of a large number of students can take a long time.  These routines allow grades to
+be computed offline, by a batch process (eg cronjob).
+
+The grades are stored in the OfflineComputedGrade table of the courseware model.
+"""
 import json
 import time
 
@@ -49,7 +50,7 @@ def offline_grade_calculation(course_key):
 
         gradeset = grades.grade(student, request, course, keep_raw_scores=True)
         gs = enc.encode(gradeset)
-        ocg, created = models.OfflineComputedGrade.objects.get_or_create(user=student, course_id=course_key)
+        ocg, _created = models.OfflineComputedGrade.objects.get_or_create(user=student, course_id=course_key)
         ocg.gradeset = gs
         ocg.save()
         print "%s done" % student  	# print statement used because this is run by a management command
diff --git a/lms/djangoapps/instructor/tests/test_api.py b/lms/djangoapps/instructor/tests/test_api.py
index 1a3ea1e377..45db5ed5a7 100644
--- a/lms/djangoapps/instructor/tests/test_api.py
+++ b/lms/djangoapps/instructor/tests/test_api.py
@@ -13,7 +13,6 @@ from nose.tools import raises
 from mock import Mock, patch
 from django.conf import settings
 from django.test.utils import override_settings
-from django.conf import settings
 from django.core.urlresolvers import reverse
 from django.http import HttpRequest, HttpResponse
 from django_comment_common.models import FORUM_ROLE_COMMUNITY_TA, Role
diff --git a/lms/djangoapps/instructor/tests/test_enrollment.py b/lms/djangoapps/instructor/tests/test_enrollment.py
index 4ce954ae2a..ddc0c69329 100644
--- a/lms/djangoapps/instructor/tests/test_enrollment.py
+++ b/lms/djangoapps/instructor/tests/test_enrollment.py
@@ -9,7 +9,6 @@ from courseware.models import StudentModule
 from django.conf import settings
 from django.test import TestCase
 from django.test.utils import override_settings
-from django.test.client import RequestFactory
 from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.factories import CourseFactory
 from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
@@ -27,7 +26,6 @@ from xmodule.modulestore.locations import SlashSeparatedCourseKey
 
 from submissions import api as sub_api
 from student.models import anonymous_id_for_user
-from .test_tools import msk_from_problem_urlname
 
 
 class TestSettableEnrollmentState(TestCase):
diff --git a/lms/djangoapps/instructor/tests/test_legacy_gradebook.py b/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
index 522e0dac2f..fddeef7772 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
@@ -11,7 +11,6 @@ from courseware.tests.tests import TEST_DATA_MIXED_MODULESTORE
 from capa.tests.response_xml_factory import StringResponseXMLFactory
 from courseware.tests.factories import StudentModuleFactory
 from xmodule.modulestore import Location
-from xmodule.modulestore.locations import SlashSeparatedCourseKey
 from xmodule.modulestore.django import modulestore
 
 
diff --git a/lms/djangoapps/instructor/tests/test_legacy_reset.py b/lms/djangoapps/instructor/tests/test_legacy_reset.py
index 9a7112ed0f..a6a6beaecb 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_reset.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_reset.py
@@ -16,7 +16,6 @@ from courseware.models import StudentModule
 
 from submissions import api as sub_api
 from student.models import anonymous_id_for_user
-from .test_tools import msk_from_problem_urlname
 
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
diff --git a/lms/djangoapps/notes/api.py b/lms/djangoapps/notes/api.py
index b8bc4f5402..d782d7543c 100644
--- a/lms/djangoapps/notes/api.py
+++ b/lms/djangoapps/notes/api.py
@@ -148,7 +148,7 @@ def create(request, course_key):
     return ApiResponse(http_response=response, data=None)
 
 
-def read(request, course_key, note_id):
+def read(request, course_key, note_id):  # pylint: disable=unused-argument (course_key)
     '''
     Returns a single annotation object.
     '''
@@ -163,7 +163,7 @@ def read(request, course_key, note_id):
     return ApiResponse(http_response=HttpResponse(), data=note.as_dict())
 
 
-def update(request, course_key, note_id):
+def update(request, course_key, note_id):  # pylint: disable=unused-argument (course_key)
     '''
     Updates an annotation object and returns a 303 with the read location.
     '''
@@ -247,7 +247,7 @@ def search(request, course_key):
     return ApiResponse(http_response=HttpResponse(), data=result)
 
 
-def root(request, course_key):
+def root(request, course_key):  # pylint: disable=unused-argument (course_key, request)
     '''
     Returns version information about the API.
     '''
diff --git a/lms/djangoapps/psychometrics/management/commands/init_psychometrics.py b/lms/djangoapps/psychometrics/management/commands/init_psychometrics.py
index c94c4abb82..c61eabfb68 100644
--- a/lms/djangoapps/psychometrics/management/commands/init_psychometrics.py
+++ b/lms/djangoapps/psychometrics/management/commands/init_psychometrics.py
@@ -7,7 +7,6 @@ import json
 from courseware.models import StudentModule
 from track.models import TrackingLog
 from psychometrics.models import PsychometricData
-from xmodule.modulestore.keys import UsageKey
 
 from django.conf import settings
 from django.core.management.base import BaseCommand