class ReportFormat(object):
   PDF = 0
   TEXT = 1
class Report(object):
   def __init__(self, format_):
      self.title = 'Monthly report'
      self.text = ['Things are going', 'really, really well.']
      self.format_ = format_

class Handler(object):
   def __init__(self):
      self.nextHandler = None

   def handle(self, request):
      self.nextHandler.handle(request)

class PDFHandler(Handler):

   def handle(self, request):
      if request.format_ == ReportFormat.PDF:
         self.output_report(request.title, request.text)
      else:
         super(PDFHandler, self).handle(request)
    
   def output_report(self, title, text):
      print ''
      print ' '
      print ' ' % title
      print ' '
      print ' '
      for line in text:
         print ' 
%s' % line
      print ' '
      print ''

class TextHandler(Handler):
   
   def handle(self, request):
      if request.format_ == ReportFormat.TEXT:
         self.output_report(request.title, request.text)
      else:
         super(TextHandler, self).handle(request)
   
   def output_report(self, title, text):
      print 5*'*' + title + 5*'*'
      for line in text:
         print line

class ErrorHandler(Handler):
   def handle(self, request):
      print "Invalid request"

if __name__ == '__main__':
   report = Report(ReportFormat.TEXT)
   pdf_handler = PDFHandler()
   text_handler = TextHandler()

   pdf_handler.nextHandler = text_handler
   text_handler.nextHandler = ErrorHandler()
    pdf_handler.handle(report)