code: def SetDefaultValue(self, scan_object):
      
      if (not isinstance(scan_object, PathFilterScanTreeNode) and
          not isinstance(scan_object, py2to3.STRING_TYPES)):
        raise TypeError('Unsupported scan object type.')
  
      if self.default_value:
        raise ValueError('Default value already set.')
  
      self.default_value = scan_object
docs: Sets the default (non-match) value.
  
      Args:
        scan_object: a scan object, either a scan tree sub node (instance of
                     PathFilterScanTreeNode) or a string containing a path.
  
      Raises:
        TypeError: if the scan object is of an unsupported type.
        ValueError: if the default value is already set.