We suggest that writing lesson plays can be a valuable approach in learning to teach proving in teacher education. A lesson play is an imagined discussion between a teacher and some students about a particular mathematical content, written verbatim. In this paper, we investigate novice teachers' opportunities to work on teaching practices related to proving by generic examples through writing lesson plays. We analyse lesson plays written by 14 novice teachers, and our analysis reveals that several teaching practices are involved. Some of the teaching practices are related to teaching mathematics in general, some are more specifically related to teaching of proving, and some of the practices are particular to teaching of proving by generic examples.