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": "is_valid_parentheses", "description": "Checks if a string contains valid parentheses.", "parameters": {"s": {"description": "The input string.", "type": "str"}}}, {"name": "format_date", "description": "Converts a date string from one format to another.", "parameters": {"date": {"description": "The date string to convert.", "type": "str"}, "input_format": {"description": "The format of the input date string.", "type": "str"}, "output_format": {"description": "The desired format of the output date string.", "type": "str"}}}, {"name": "find_longest_word", "description": "Finds the longest word in a list of words.", "parameters": {"words": {"description": "A list of words.", "type": "List[str]"}}}]
Find the longest word in the list ['hello', 'world', 'python'].
user
assistant
[{"name": "find_longest_word", "arguments": {"words": ["hello", "world", "python"]}}]