title: No Locust class found when running locustfile
body: <p>I am just getting started with Locust.  Here is my locustfile.py</p>
  
  <pre><code>from locust import HttpLocust, TaskSet, between, TaskSequence
  
  def select_user(l):
      pass
  
  def get_company(l, company):
  
      target = "https://URL"
      print(f"Company: {company} URL: {target}")
  
      response = l.client.get(target, {"name": company })
  
      return response
  
  class UserBehavior(TaskSequence):
  
      def on_start(self):
          response = get_company(self, "LoadTest")
          print(response)
  
      # @seq_task(1)
      # def first_task(self):
      #     pass
  
  class User(HttpLocust):
      tasks = [UserBehavior]
      wait_time = between(5, 60)
  </code></pre>
  
  <p>when I run locust in the same directory as locustfile.py I  get the error:</p>
  
  <pre><code>% locust
  [2020-05-15 20:43:08,131] host/ERROR/locust.main: No Locust class found!
  </code></pre>
  
  <p>It is unclear to me what  I  have wrong.  I am using TaskSequence because once I get  this working, I will be adding tasks which must be executed in a specific order.</p>
  
  <p>Additionally, if I uncomment the @seq_task(1) decorator I get an error  that <code>seq_task</code> is not defined.  </p>
  
  <p>This is on</p>
  
  <pre><code>% locust --version
  locust 0.14.4
  </code></pre>