Write a function named compare_list that takes two lists and returns True if they have at least one common element, and returns False otherwise.

Here's a Python function named `compare_list` that takes two lists and returns `True` if they have at least one common element, and returns `False` otherwise:

def compare_list(list1, list2):
    for item in list1:
        if item in list2:
            return True
    return False

In this function, we loop through each item in `list1`, and check if it exists in `list2`. If we find a common element, we immediately return `True`. If we've looped through all of `list1` without finding a common element, we return `False`.

You can call this function with your own lists as follows:

list1 = [1, 2, 3, 4, 5]
list2 = [6, 7, 8, 9, 10]
result1 = compare_list(list1, list2)
print(result1) # False

list3 = [1, 2, 3, 4, 5]
list4 = [5, 6, 7, 8, 9]
result2 = compare_list(list3, list4)
print(result2) # True