old_contents: import re
  from reportlab import platypus
  from facturapdf import flowables, helper
  
  
  def element(item):
      elements = {
          'framebreak': {'class': platypus.FrameBreak},
          'simpleline': {'class': flowables.SimpleLine, 'cast': {0: float, 1: float}},
          'paragraph':  {'class': flowables.Paragraph},
          'image':      {'class': helper.get_image, 'cast': {1: float}},
          'spacer':     {'class': platypus.Spacer, 'cast': {0: float, 1: float}}
      }
  
      if isinstance(item, str):
          match = re.search('(?P<name>\w+)(\[(?P<args>.+)\])?', item)
  
          if match and match.group('name') in elements:
              flowable = elements[match.group('name')]
              args = [] if not match.group('args') else match.group('args').split('|')
  
              if 'cast' in flowable:
                  for index, cls in flowable['cast'].iteritems():
                      args[index] = cls(args[index])
  
              return flowable['class'](*args)
  
      return item
  
  
  def chapter(*args):
      return [element(item) for item in args]
new_contents: import re
  from reportlab import platypus
  from facturapdf import flowables, helper
  
  
  def element(item):
      elements = {
          'framebreak': {'class': platypus.FrameBreak},
          'simpleline': {'class': flowables.SimpleLine, 'cast': {0: float, 1: float}},
          'paragraph':  {'class': flowables.Paragraph},
          'image':      {'class': helper.get_image, 'cast': {1: float}},
          'spacer':     {'class': platypus.Spacer, 'cast': {0: float, 1: float}}
      }
  
      if isinstance(item, str):
          match = re.search('(?P<name>\w+)(\[(?P<args>.+)\])?', item)
  
          if match and match.group('name') in elements:
              flowable = elements[match.group('name')]
              args = [] if not match.group('args') else match.group('args').split('|')
  
              if 'cast' in flowable:
                  for index, cls in iter(flowable['cast'].items()):
                      args[index] = cls(args[index])
  
              return flowable['class'](*args)
  
      return item
  
  
  def chapter(*args):
      return [element(item) for item in args]
subject: Use dict iteration compatible with Python 2 and 3