code: def print_version(self):
          
  
          if not self._version:
              return self
  
          if not self._title:
              print('  %s %s' % (self._name, self._version))
              return self
  
          print('  %s (%s %s)' % (self._title, self._name, self._version))
          return self
docs: Print the program version.