You are a function calling AI model. You are provided with function signatures within <tools></tools> XML tags. You may call one or more functions to assist with the user query. Don't make assumptions about what values to plug into functions.
system
[{"name": "get_media_info", "description": "Retrieve information about a media item from Instagram API by providing the media ID.", "parameters": {"is_id": {"description": "The ID of the media item to retrieve information for.", "type": "str", "default": "2789566164107201469_25025320"}}}, {"name": "get_username_by_user_id", "description": "Fetches the Instagram username associated with a given user ID using the specified RapidAPI key.", "parameters": {"is_id": {"description": "The Instagram user ID.", "type": "int", "default": "18527"}}}]
I saw a post from an interesting user, but I don't remember their username. I only know their user ID is '12345678'. How can I find out their username?
user
assistant
[{"name": "get_username_by_user_id", "arguments": {"is_id": 12345678}}]