What was Plato's definition of poetry before Aristotle's definition of poetry, and was it influenced by Aristotle?

Because Plato was Aristotle's teacher, it is unlikely that
works of Plato directly respond to Aristotle; rather, Aristotle's work was written in
response to Plato. Both Aristotle and Plato shared a concern about the moral effect of
poetry. For Plato, poetry was morally problematic for two reasons. On the level of
content, it showed the gods behaving in an imoral fashion. Formally, it acted by means
of imitation, and rather than imitating the forms, only imitated phenomena which
themselves imitated forms. For Aristotle, poetry could serve a useful function by using
fictional examples to train and purify the emotions.