def p_inheritance(self, p):
if p[<NUM_LIT:1>]:<EOL><INDENT>if p[<NUM_LIT:2>].nullable:<EOL><INDENT>msg = '<STR_LIT>'<EOL>self.errors.append((msg, p.lineno(<NUM_LIT:1>), self.path))<EOL><DEDENT>else:<EOL><INDENT>p[<NUM_LIT:0>] = p[<NUM_LIT:2>]<EOL><DEDENT><DEDENT>
inheritance : EXTENDS type_ref
                       | empty