code: def open_machine(self, settings_file):
          
          if not isinstance(settings_file, basestring):
              raise TypeError("settings_file can only be an instance of type basestring")
          machine = self._call("openMachine",
                       in_p=[settings_file])
          machine = IMachine(machine)
          return machine
docs: Opens a virtual machine from the existing settings file.
          The opened machine remains unregistered until you call
          :py:func:`register_machine` .
          
          The specified settings file name must be fully qualified.
          The file must exist and be a valid machine XML settings file
          whose contents will be used to construct the machine object.
          
          
          :py:func:`IMachine.settings_modified`  will return
          @c false for the opened machine, until any of machine settings
          are changed.
  
          in settings_file of type str
              Name of the machine settings file.
  
          return machine of type :class:`IMachine`
              Opened machine object.
  
          raises :class:`VBoxErrorFileError`
              Settings file name invalid, not found or sharing violation.