Rule reminder
Special rule: when a DIRECT OBJECT PRONOUN (lo, la, li, le) comes BEFORE the passato prossimo, the past participle MUST agree with the pronoun: Lo ho visto → L'ho visto (masc. sing.); La ho vista → L'ho vista (fem. sing.); Li ho visti (masc. plural); Le ho viste (fem. plural).
WITH a pronoun, which is correct? 'I ate it (la pizza).'