title: TypeError: __str__ returned non-string
body: <pre><code>class Course(object):
      def __init__(self,cnum,name):
          self.name = name
          self.cnum = cnum
      def __str__(self):
          return 'Course:' , self.cnum  , self.name
  
  class AssigendCourse(Course):
      def __init__(self,Course,dept,year,semester):
          self.name = Course.name
          self.cnum = Course.cnum
          if dept == 'SE' or dept == 'CE' or dept == 'CIE' or dept == 'ME':
              self.dept = dept
          else:
              self.dept = None
          if year &gt;= 1 and year &lt;= 4:
              self.year = year
          else:
              self.year = None
          if semester &gt;= 1 and semester &lt;= 3:
              self.semester = semester
          else:
              self.semester = None
      def __str__(self):
          return 'Course: ' , self.name , self.cnum
  </code></pre>
  
  <p>results in this type of error</p>
  
  <pre><code>TypeError: __str__ returned non-string (type tuple)
  </code></pre>
  
  <p>I can't figure what type of syntax I need to use for the <code>__str__</code> func in order to get the print for the object when using:</p>
  
  <pre><code>it = iter(db)
  for i in it:
      print(i)
  </code></pre>