title: NameError: class name is not defined
body: <p>I can't find why this piece of code won't work:</p>
  
  <pre><code>class Agent:
  def hello(self, first_name):
      return "Bien le bonjour" + first_name + "!"
  agent = Agent()
  print(agent.hello("Félix"))
  </code></pre>
  
  <p>I'm pretty sure to run it under python3 since i just follow a tutorial: <a href="https://www.digitalocean.com/community/tutorials/how-to-install-python-3-and-set-up-a-local-programming-environment-on-ubuntu-16-04" rel="noreferrer">https://www.digitalocean.com/community/tutorials/how-to-install-python-3-and-set-up-a-local-programming-environment-on-ubuntu-16-04</a>
  on how to create a local envirement for python3.</p>
  
  <p>It return <code>class Agent:
    File "la_poo_avec_python-00_setup/model.py", line 4, in Agent
      agent = Agent()
  NameError: name 'Agent' is not defined
  (my_env) noob@Flex:~/Noobi/prog/python3env/my_env$</code></p>