title: Python: I can't assign a defined list to the class attribute?
body: <pre><code>class Runner:
      """
      information of registered runners
      Attributes:
          @type email: str
          email of the registered runner
          @type category: str
          the speed they estimate that they can finish the race
          @type list: clist
          the list of runners in the same category
  
      """
      under_twenty_min = []
      under_thirty_min = []
      under_forty_min = []
      forty_and_above = []
  
      def __init__(self, email, category):
          """Register the email and the speed estimation of runners
  
              @type self: Runner
              @type email: str
              @type speed: int
              @type category:str
              @type clist: list
              @rtype: list
  
          &gt;&gt;&gt;runner1=Runner('gerhard@mail.utoronto.ca','under 40 min')
          &gt;&gt;&gt;runner1.email
          'gerhard@gmail.utoronto.ca'
          &gt;&gt;&gt;runner1.category
          'under 40 min'
          """
          self.email = email
          self.category = category
          if category=='under 20 min':
              self.clist=under_twenty_min
          elif category=='under 30 min':
              self.clist = under_twenty_min
          elif  category=='under 40 min':
              self.clist = under_forty_min
          elif category=='40 min and over':
              self.clist = forty_and_over
          renew(self,clist)
          return clist
  </code></pre>
  
  <p>basically i have to return a list of runners with the same speed category when initialize a runner, but I can't assign the lists I defined above to the class attribute, is there anyway to fix it?</p>