diff --git a/cps.py b/cps.py
index 50ab0076..737b0d97 100755
--- a/cps.py
+++ b/cps.py
@@ -31,7 +31,7 @@ else:
     sys.path.append(os.path.join(os.path.dirname(os.path.abspath(__file__)), 'vendor'))
 
 
-from cps import create_app, config
+from cps import create_app
 from cps import web_server
 from cps.opds import opds
 from cps.web import web
diff --git a/cps/helper.py b/cps/helper.py
index 506afe71..50e24636 100644
--- a/cps/helper.py
+++ b/cps/helper.py
@@ -32,7 +32,7 @@ from tempfile import gettempdir
 import requests
 from babel.dates import format_datetime
 from babel.units import format_unit
-from flask import send_from_directory, make_response, redirect, abort, url_for, send_file
+from flask import send_from_directory, make_response, redirect, abort, url_for
 from flask_babel import gettext as _
 from flask_login import current_user
 from sqlalchemy.sql.expression import true, false, and_, text
diff --git a/cps/kobo.py b/cps/kobo.py
index 3210a450..39032f3b 100644
--- a/cps/kobo.py
+++ b/cps/kobo.py
@@ -43,7 +43,6 @@ from flask_login import current_user
 from werkzeug.datastructures import Headers
 from sqlalchemy import func
 from sqlalchemy.sql.expression import and_, or_
-from sqlalchemy.exc import OperationalError
 from sqlalchemy.orm import load_only
 from sqlalchemy.exc import StatementError
 import requests
diff --git a/cps/kobo_auth.py b/cps/kobo_auth.py
index ba35c78b..1ede03a4 100644
--- a/cps/kobo_auth.py
+++ b/cps/kobo_auth.py
@@ -66,7 +66,6 @@ from os import urandom
 from flask import g, Blueprint, url_for, abort, request
 from flask_login import login_user, login_required
 from flask_babel import gettext as _
-from sqlalchemy.exc import OperationalError
 
 from . import logger, ub, lm
 from .render_template import render_title_template
diff --git a/cps/oauth_bb.py b/cps/oauth_bb.py
index b6474758..b17d38c7 100644
--- a/cps/oauth_bb.py
+++ b/cps/oauth_bb.py
@@ -32,7 +32,6 @@ from flask_dance.contrib.github import make_github_blueprint, github
 from flask_dance.contrib.google import make_google_blueprint, google
 from flask_login import login_user, current_user, login_required
 from sqlalchemy.orm.exc import NoResultFound
-from sqlalchemy.exc import OperationalError
 
 from . import constants, logger, config, app, ub
 
diff --git a/cps/web.py b/cps/web.py
index 82378de8..c85c0175 100644
--- a/cps/web.py
+++ b/cps/web.py
@@ -47,7 +47,7 @@ from werkzeug.security import generate_password_hash, check_password_hash
 
 from . import constants, logger, isoLanguages, services
 from . import babel, db, ub, config, get_locale, app
-from . import calibre_db, shelf
+from . import calibre_db
 from .gdriveutils import getFileFromEbooksFolder, do_gdrive_download
 from .helper import check_valid_domain, render_task_status, \
     get_cc_columns, get_book_cover, get_download_link, send_mail, generate_random_password, \