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": "light_travel_time", "description": "Calculate the time taken for light to travel from one celestial body to another.", "parameters": {"distance_in_light_years": {"description": "The distance between the two celestial bodies in light years.", "type": "int", "default": 299792458}, "speed_of_light": {"description": "The speed of light in vacuum, in m/s. Default value is 299792458 m/s.", "type": "int", "default": 299792458}}}]
What is the time taken for light to travel a distance of 1000 light years?
user
assistant
[{"name": "light_travel_time", "arguments": {"distance_in_light_years": 1000}}]