django "python manage.py validate" error : unknown command 'validate'
With python manage.py these commands are listed:

Available subcommands:
[auth]
changepassword
createsuperuser
[django]
check
compilemessages
createcachetable
dbshell
diffsettings
dumpdata
flush
inspectdb
loaddata
makemessages
makemigrations
migrate
sendtestemail
shell
showmigrations
sqlflush
sqlmigrate
sqlsequencereset
squashmigrations
startapp
startproject
test
testserver
[sessions]
clearsessions
[staticfiles]
collectstatic
findstatic
runserver

There is no "validate" command in the list.
With running this command:

python manage.py validate

I faced with this error:

Unknown command: 'validate'

What should I do now?
For more explanations:

Linux
Virtualenv
Python 3.4.3+
Django (1, 9, 2, 'final', 0)