def __lt__(self, other):
if not isinstance(other, XCSClassifierRule):<EOL><INDENT>return NotImplemented<EOL><DEDENT>attribute_order = (<EOL>'<STR_LIT>',<EOL>'<STR_LIT>',<EOL>'<STR_LIT>',<EOL>'<STR_LIT:error>',<EOL>'<STR_LIT>',<EOL>'<STR_LIT>',<EOL>'<STR_LIT>'<EOL>)<EOL>for attribute in attribute_order:<EOL><INDENT>my_key = getattr(self, attribute)<EOL>other_key = getattr(other, attribute)<EOL>if my_key < other_key:<EOL><INDENT>return attribute not in ('<STR_LIT:error>', '<STR_LIT>')<EOL><DEDENT>if my_key > other_key:<EOL><INDENT>return attribute in ('<STR_LIT:error>', '<STR_LIT>')<EOL><DEDENT><DEDENT>return False<EOL>
Defining this sets the behavior for instance1 < instance2. This
        is here strictly for sorting purposes in calls to
        ClassifierSet.__str__.