UndefinedError: 'register_form' is undefined

    jinja2.exceptions.UndefinedError
    UndefinedError: 'register_form' is undefined

        Traceback (most recent call last)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1994, in __call__
        return self.wsgi_app(environ, start_response)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask_socketio/__init__.py", line 42, in __call__
        start_response)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/engineio/middleware.py", line 49, in __call__
        return self.wsgi_app(environ, start_response)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1985, in wsgi_app
        response = self.handle_exception(e)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1540, in handle_exception
        reraise(exc_type, exc_value, tb)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1982, in wsgi_app
        response = self.full_dispatch_request()
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
        rv = self.handle_user_exception(e)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1517, in handle_user_exception
        reraise(exc_type, exc_value, tb)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
        rv = self.dispatch_request()
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask_debugtoolbar/__init__.py", line 125, in dispatch_request
        return view_func(**req.view_args)
        File "/home/reznov/Desktop/ubook/develop/client/views.py", line 107, in index
        return render_template('index.html', form_login=form_login)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/templating.py", line 134, in render_template
        context, ctx.app)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/flask/templating.py", line 116, in _render
        rv = template.render(context)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/jinja2/environment.py", line 1008, in render
        return self.environment.handle_exception(exc_info, True)
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/jinja2/environment.py", line 780, in handle_exception
        reraise(exc_type, exc_value, tb)
        File "/home/reznov/Desktop/ubook/develop/abonent/templates/abonent/index.html", line 1, in top-level template code
        {% extends 'base_abonent.html' %}
        File "/home/reznov/Desktop/ubook/develop/templates/base_abonent.html", line 41, in top-level template code
        {% block content %}
        File "/home/reznov/Desktop/ubook/develop/abonent/templates/abonent/index.html", line 196, in block "content"
        {{register_form.master_salon.label}}
        File "/home/reznov/Desktop/ubook/venv/lib/python2.7/site-packages/jinja2/environment.py", line 430, in getattr
        return getattr(obj, attribute)
        UndefinedError: 'register_form' is undefined