diff --git a/web/migrations/script.py.mako b/web/migrations/script.py.mako
index c8b4c12d3..02d4a0fcc 100644
--- a/web/migrations/script.py.mako
+++ b/web/migrations/script.py.mako
@@ -30,4 +30,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     ${downgrades if downgrades else "pass"}
diff --git a/web/migrations/versions/02b9dccdcfcb_.py b/web/migrations/versions/02b9dccdcfcb_.py
index 185eb2156..5d53275a4 100644
--- a/web/migrations/versions/02b9dccdcfcb_.py
+++ b/web/migrations/versions/02b9dccdcfcb_.py
@@ -31,5 +31,7 @@ def upgrade():
         'ALTER TABLE server ADD COLUMN fgcolor TEXT(10)'
     )
 
+
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/09d53fca90c7_.py b/web/migrations/versions/09d53fca90c7_.py
index 3a31262a5..bd329319a 100644
--- a/web/migrations/versions/09d53fca90c7_.py
+++ b/web/migrations/versions/09d53fca90c7_.py
@@ -229,9 +229,5 @@ def upgrade():
 
 
 def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    print(u"""
-    Cannot downgrade from this version
-    Exiting...""")
-    sys.exit(1)
-    # ### end Alembic commands ###
+    # pgAdmin only upgrades, downgrade not implemented.
+    pass
diff --git a/web/migrations/versions/35f29b1701bd_.py b/web/migrations/versions/35f29b1701bd_.py
index 8797ef1db..1180e7d89 100644
--- a/web/migrations/versions/35f29b1701bd_.py
+++ b/web/migrations/versions/35f29b1701bd_.py
@@ -48,4 +48,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/3c1e4b6eda55_.py b/web/migrations/versions/3c1e4b6eda55_.py
index cd9bf67a6..aa4018a77 100644
--- a/web/migrations/versions/3c1e4b6eda55_.py
+++ b/web/migrations/versions/3c1e4b6eda55_.py
@@ -23,4 +23,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/493cd3e39c0c_.py b/web/migrations/versions/493cd3e39c0c_.py
index fa37750b7..371ec4fb6 100644
--- a/web/migrations/versions/493cd3e39c0c_.py
+++ b/web/migrations/versions/493cd3e39c0c_.py
@@ -25,4 +25,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/50aad68f99c2_.py b/web/migrations/versions/50aad68f99c2_.py
index 4cda56bdb..cadd2e445 100644
--- a/web/migrations/versions/50aad68f99c2_.py
+++ b/web/migrations/versions/50aad68f99c2_.py
@@ -78,5 +78,7 @@ def upgrade():
             'ALTER TABLE server ADD COLUMN service TEXT'
         )
 
+
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/7c56ea250085_.py b/web/migrations/versions/7c56ea250085_.py
index 24af34981..54a08588c 100644
--- a/web/migrations/versions/7c56ea250085_.py
+++ b/web/migrations/versions/7c56ea250085_.py
@@ -86,5 +86,7 @@ def upgrade():
     # Remove old data
     db.engine.execute("DROP TABLE server_old")
 
+
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/7fedf8531802_.py b/web/migrations/versions/7fedf8531802_.py
index 89401686a..4d055c829 100644
--- a/web/migrations/versions/7fedf8531802_.py
+++ b/web/migrations/versions/7fedf8531802_.py
@@ -48,4 +48,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/84700139beb0_.py b/web/migrations/versions/84700139beb0_.py
index 455fd3d9b..10f26a98e 100644
--- a/web/migrations/versions/84700139beb0_.py
+++ b/web/migrations/versions/84700139beb0_.py
@@ -29,4 +29,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/a68b374fe373_.py b/web/migrations/versions/a68b374fe373_.py
index 5e94bb1e2..1db15d658 100644
--- a/web/migrations/versions/a68b374fe373_.py
+++ b/web/migrations/versions/a68b374fe373_.py
@@ -37,5 +37,7 @@ def upgrade():
         'ALTER TABLE server ADD COLUMN tunnel_identity_file TEXT'
     )
 
+
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/a77a0932a568_.py b/web/migrations/versions/a77a0932a568_.py
index 76ad244bf..2702aa279 100644
--- a/web/migrations/versions/a77a0932a568_.py
+++ b/web/migrations/versions/a77a0932a568_.py
@@ -88,4 +88,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/aa86fb60b73d_.py b/web/migrations/versions/aa86fb60b73d_.py
index 1581af4c5..0dad53299 100644
--- a/web/migrations/versions/aa86fb60b73d_.py
+++ b/web/migrations/versions/aa86fb60b73d_.py
@@ -29,4 +29,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/aff1436e3c8c_.py b/web/migrations/versions/aff1436e3c8c_.py
index 7a7c3017d..7be0428a7 100644
--- a/web/migrations/versions/aff1436e3c8c_.py
+++ b/web/migrations/versions/aff1436e3c8c_.py
@@ -24,4 +24,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/b5b87fdfcb30_.py b/web/migrations/versions/b5b87fdfcb30_.py
index 124606fc9..076a80bb1 100644
--- a/web/migrations/versions/b5b87fdfcb30_.py
+++ b/web/migrations/versions/b5b87fdfcb30_.py
@@ -30,4 +30,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/ca00ec32581b_.py b/web/migrations/versions/ca00ec32581b_.py
index cd6bf6877..635539002 100644
--- a/web/migrations/versions/ca00ec32581b_.py
+++ b/web/migrations/versions/ca00ec32581b_.py
@@ -31,4 +31,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/d39482714a2e_.py b/web/migrations/versions/d39482714a2e_.py
index 66a51db87..039ca5332 100644
--- a/web/migrations/versions/d39482714a2e_.py
+++ b/web/migrations/versions/d39482714a2e_.py
@@ -43,5 +43,7 @@ def upgrade():
         """
     )
 
+
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/d85a62333272_.py b/web/migrations/versions/d85a62333272_.py
index 0b16faf93..856362081 100644
--- a/web/migrations/versions/d85a62333272_.py
+++ b/web/migrations/versions/d85a62333272_.py
@@ -23,4 +23,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/ec1cac3399c9_.py b/web/migrations/versions/ec1cac3399c9_.py
index e6739dfcb..d8e0349b5 100644
--- a/web/migrations/versions/ec1cac3399c9_.py
+++ b/web/migrations/versions/ec1cac3399c9_.py
@@ -39,4 +39,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/ece2e76bf60e_.py b/web/migrations/versions/ece2e76bf60e_.py
index 2142f65f8..6ab954076 100644
--- a/web/migrations/versions/ece2e76bf60e_.py
+++ b/web/migrations/versions/ece2e76bf60e_.py
@@ -31,4 +31,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/ef590e979b0d_.py b/web/migrations/versions/ef590e979b0d_.py
index be219c511..2c9d422d8 100644
--- a/web/migrations/versions/ef590e979b0d_.py
+++ b/web/migrations/versions/ef590e979b0d_.py
@@ -43,4 +43,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/migrations/versions/f195f9a4923d_.py b/web/migrations/versions/f195f9a4923d_.py
index 2402565bc..0c8132d9b 100644
--- a/web/migrations/versions/f195f9a4923d_.py
+++ b/web/migrations/versions/f195f9a4923d_.py
@@ -45,4 +45,5 @@ def upgrade():
 
 
 def downgrade():
+    # pgAdmin only upgrades, downgrade not implemented.
     pass
diff --git a/web/pgadmin/browser/server_groups/servers/databases/schemas/utils.py b/web/pgadmin/browser/server_groups/servers/databases/schemas/utils.py
index 3fd55868d..402cf5c22 100644
--- a/web/pgadmin/browser/server_groups/servers/databases/schemas/utils.py
+++ b/web/pgadmin/browser/server_groups/servers/databases/schemas/utils.py
@@ -501,9 +501,6 @@ class VacuumSettings:
     """
     vacuum_settings = dict()
 
-    def __init__(self):
-        pass
-
     def fetch_default_vacuum_settings(self, conn, sid, setting_type):
         """
         This function is used to fetch and cached the default vacuum settings
diff --git a/web/pgadmin/misc/bgprocess/process_executor.py b/web/pgadmin/misc/bgprocess/process_executor.py
index 1569c97d9..074554933 100755
--- a/web/pgadmin/misc/bgprocess/process_executor.py
+++ b/web/pgadmin/misc/bgprocess/process_executor.py
@@ -371,8 +371,8 @@ def execute(argv):
         _log('Bye!')
 
 
-# Let's ignore all the signal comming to us.
 def signal_handler(signal, msg):
+    # Let's ignore all the signal comming to us.
     pass
 
 
diff --git a/web/pgadmin/tools/grant_wizard/__init__.py b/web/pgadmin/tools/grant_wizard/__init__.py
index 9d387287b..79c5529c4 100644
--- a/web/pgadmin/tools/grant_wizard/__init__.py
+++ b/web/pgadmin/tools/grant_wizard/__init__.py
@@ -19,7 +19,7 @@ from urllib.parse import unquote
 from pgadmin.browser.server_groups.servers.utils import parse_priv_to_db
 from pgadmin.utils import PgAdminModule
 from pgadmin.utils.ajax import make_response as ajax_response, \
-    make_json_response, internal_server_error
+    make_json_response, internal_server_error, bad_request
 from pgadmin.utils.driver import get_driver
 
 from config import PG_DEFAULT_DRIVER
@@ -144,7 +144,9 @@ def check_precondition(f):
 @blueprint.route("/")
 @login_required
 def index():
-    pass
+    return bad_request(
+        errormsg=gettext("This URL cannot be called directly.")
+    )
 
 
 @blueprint.route("/grant_wizard.js")
diff --git a/web/pgadmin/utils/__init__.py b/web/pgadmin/utils/__init__.py
index 6e470a943..2da8bd0f1 100644
--- a/web/pgadmin/utils/__init__.py
+++ b/web/pgadmin/utils/__init__.py
@@ -52,6 +52,7 @@ class PgAdminModule(Blueprint):
         self.before_app_first_request(create_module_preference)
 
     def register_preferences(self):
+        # To be implemented by child classes
         pass
 
     def register(self, app, options, first_registration=False):
diff --git a/web/regression/feature_utils/base_feature_test.py b/web/regression/feature_utils/base_feature_test.py
index 4c41474c1..ac5e78e73 100644
--- a/web/regression/feature_utils/base_feature_test.py
+++ b/web/regression/feature_utils/base_feature_test.py
@@ -48,12 +48,15 @@ class BaseFeatureTest(BaseTestGenerator):
             raise
 
     def runTest(self):
+        # To be implemented by child classes
         pass
 
     def before(self):
+        # To be implemented by child classes
         pass
 
     def after(self):
+        # To be implemented by child classes
         pass
 
     def tearDown(self):
diff --git a/web/regression/python_test_utils/sql_template_test_base.py b/web/regression/python_test_utils/sql_template_test_base.py
index ec169d853..91ff5d135 100644
--- a/web/regression/python_test_utils/sql_template_test_base.py
+++ b/web/regression/python_test_utils/sql_template_test_base.py
@@ -28,12 +28,15 @@ class SQLTemplateTestBase(BaseTestGenerator):
         self.database_name = -1
 
     def test_setup(self, connection, cursor):
+        # To be implemented by child classes
         pass
 
     def generate_sql(self, version):
+        # To be implemented by child classes
         pass
 
     def assertions(self, fetch_result, descriptions):
+        # To be implemented by child classes
         pass
 
     def runTest(self):
diff --git a/web/regression/runtests.py b/web/regression/runtests.py
index bcb7b2a62..067cdcae8 100644
--- a/web/regression/runtests.py
+++ b/web/regression/runtests.py
@@ -410,6 +410,7 @@ class StreamToLogger(object):
             self.logger.log(self.log_level, line.rstrip())
 
     def flush(self):
+        # Function required to be implemented for logger
         pass