user: I'm planning a movie night for my family this weekend, and I want to make sure the film is appropriate for all ages. We've settled on the idea of watching "Avatar", but I need to confirm its age rating before we proceed. Could you find out the age rating for the movie "Avatar"?

Available functions:
name: get_movie_rating
description: Fetches the age rating of a movie from the OMDB API.
parameters: type: dict
properties: movie_name: type: string
description: The name of the movie.
required: movie_name
name: get_movie_genre
description: Retrieves the genre of a movie from the OMDB API.
parameters: type: dict
properties: movie_name: type: string
description: The name of the movie to retrieve the genre for.
required: movie_name
name: get_director_by_movie_name
description: Gets the director of a movie.
parameters: type: dict
properties: movie_name: type: string
description: The movie to find the director of.
required: movie_name