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": "count_vowels", "description": "Counts the number of vowels in a given text.", "parameters": {"text": {"description": "The input text.", "type": "str"}}}, {"name": "is_rotation", "description": "Checks if one string is a rotation of another string.", "parameters": {"str1": {"description": "The first string.", "type": "str"}, "str2": {"description": "The second string.", "type": "str"}}}, {"name": "remove_duplicates", "description": "Removes duplicate elements from a list while preserving the order.", "parameters": {"lst": {"description": "The input list.", "type": "List"}}}, {"name": "calculate_age", "description": "Calculates the age based on the birthdate.", "parameters": {"birthdate": {"description": "The birthdate in the format 'YYYY-MM-DD'.", "type": "str"}}}]
How many vowels are there in the sentence 'Hello, how are you?'
user
assistant
[{"name": "count_vowels", "arguments": {"text": "Hello, how are you?"}}]