Write a function to find sum and average of first n natural numbers.
def sum_average(number):
 total = 0
 for value in range(1, number + 1):
    total = total + value
 average = total / number
 return (total,average)
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to find sum and average of first n natural numbers.
def sum_average(number):
 total = 0
 for value in range(1, number + 1):
    total = total + value
 average = total / number
 return (total,average)[/INST]assert sum_average(10)==(55, 5.5)
assert sum_average(15)==(120, 8.0)
assert sum_average(20)==(210, 10.5)</s>