Write a function to check whether a specified list is sorted or not.
def issort_list(list1):
    result = all(list1[i] <= list1[i+1] for i in range(len(list1)-1))
    return result
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to check whether a specified list is sorted or not.
def issort_list(list1):
    result = all(list1[i] <= list1[i+1] for i in range(len(list1)-1))
    return result[/INST]assert issort_list([1,2,4,6,8,10,12,14,16,17])==True
assert issort_list([1, 2, 4, 6, 8, 10, 12, 14, 20, 17])==False
assert issort_list([1, 2, 4, 6, 8, 10,15,14,20])==False</s>