title: AttributeError: 'str' object has no attribute 'n' when using dateutil
body: <p>I am using dateutil rrule function .. i get the weekdays from my data model in django. when i put it in rrule function like this</p>
  
  <pre><code>for x in lgs:
      teams = Team.objects.filter(league=x.id)
      teamcount = len(teams)
      playdays = "rrule." + str(x.play_days)
      fixdays = rrule.rrule(rrule.DAILY,byweekday = (playdays),dtstart=startdate,until=endate)
      print list(fixdays)
  
  Traceback (most recent call last):
  File "&lt;console&gt;", line 5, in &lt;module&gt;
  File "/usr/lib/pymodules/python2.7/dateutil/rrule.py", line 345, in __init__
      elif not wday.n or freq &gt; MONTHLY:
  AttributeError: 'str' object has no attribute 'n'
  </code></pre>
  
  <p>if i use the function normally, and replace line 5 with </p>
  
  <pre><code>    fixdays = rrule.rrule(rrule.DAILY,byweekday = (rrule.SU, rrule.MO),dtstart=startdate,until=endate)
  </code></pre>
  
  <p>i get no problem. what could be wrong.</p>