code: def pretty_print(self, indent=0):
          
  
          s = tab = ' '*indent
          s += '%s: ' %self.tag
          if isinstance(self.value, basestring):
              s += self.value
          else:
              s += '\n'
              for e in self.value:
                  s += e.pretty_print(indent+4)
          s += '\n'
  
          return s
docs: Print the document without tags using indentation