Sequence does not get past first nested sequence.

Description of issue

When the first sequence-task in a task sequence is a class, subsequent sequence-tasks never run.

First, I created a sequence with 3 sequence-task methods, and that worked fine. Next, I moved the first 2 steps into a nested class. Those 2 steps ran, but the remaining step in the outer sequence class did not.

If this is something I'm doing wrong, I can't figure it out, so if this is my misunderstanding, maybe we can have something in the docs to help clarify.

Environment settings

OS: CentOS 7.x
Python version: CPython 3.6
Locust version: 0.11.0

Steps to reproduce (for bug reports)

rom locust import HttpLocust, TaskSequence, task, seq_task

RAD_LOGIN_CREDENTIALS = {"email": "brad@example.com", "password": "password"}

lass UserBehavior(TaskSequence):

   def on_stop(self):
       self.logout()

   @seq_task(1)
   class Login(TaskSequence):
       min_wait = 0
       max_wait = 5

       @seq_task(1)
       def get_info(self):
           self.client.get("/api/v1/info/")

       @seq_task(2)
       def login(self):
           response = self.client.post(
               "/api/v1/private/login/", json=BRAD_LOGIN_CREDENTIALS)
           dh_token = response.json()['dh_token']
           self.client.headers['Authorization'] = f'Token {dh_token}'

   @seq_task(2)
   def view_dashboard(self):
       self.client.get(
           '/api/v1/private/tasks/',
           params={
               'additional_fields':
                   'task_id,object,workflow,actions,type_event',
               'ordering': '-udate',
               'page': '1',
               'page_size': '5',
               'roles': 'requester',
               'ticket_system': 'DesignHUB'})

   def logout(self):
       if self.client.headers.get('Authorization'):
           self.client.post("/api/v1/private/logout/")

class WebsiteUser(HttpLocust):
    task_set = UserBehavior
    min_wait = 4000
    max_wait = 7000

When I run this, I only get output for /api/v1/info/, /api/v1/private/login/, and /api/v1/private/logout/ . When I run this with all 3 sequence task methods in the outer class, numbered 1 through 3, then I also get requests to /api/v1/private/tasks/?… as expected.

locustio / locust