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_subset", "description": "Checks if one set is a subset of another set.", "parameters": {"set1": {"description": "The first set.", "type": "set"}, "set2": {"description": "The second set.", "type": "set"}}}, {"name": "word_frequency", "description": "Calculates the frequency of each word in a text.", "parameters": {"text": {"description": "The input text.", "type": "str"}}}, {"name": "is_valid_parentheses", "description": "Checks if a string contains valid parentheses.", "parameters": {"s": {"description": "The input string.", "type": "str"}}}]
Calculate the word frequency in the sentence 'Hello world, hello universe, hello world again.'
user
assistant
[{"name": "word_frequency", "arguments": {"text": "Hello world, hello universe, hello world again."}}]