Mukul is a successful teacher in his classroom, but he had not assumed a leadership role in the school. The principal asked him to guide his new teammate, a brand-new teacher and a recent immigrant from the other state. He not only helped his teammate negotiate the district, school, and classroom but also acclimated his colleague to the community. Mukul felt proud as he watched his colleague develop into an accomplished teacher.

Here, Mukul served as a ___________ for his colleague, a novice teacher.