def p_examples_add(self, p):
        'examples : examples example'
        p[0] = p[1]
        if p[2].label in p[0]:
            existing_ex = p[0][p[2].label]
            self.errors.append(
                ("Example with label '%s' already defined on line %d." %
                 (existing_ex.label, existing_ex.lineno),
                 p[2].lineno, p[2].path))
        p[0][p[2].label] = p[2]
examples : examples example