How to use this editor ? O_o

tell me or show me, how to use this editor ?

def checkio(data):
    #replace this for solution
    checkio([1, 2, 3, 4, 5])
    x=len(checkio) -1
    y=0
    while x>0:
        y+=chekio[x]
        x-=1         
    x=y/len(checkio)
    return x 
#These "asserts" using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
    assert checkio([1, 2, 3, 4, 5]) == 3, "Sorted list"
    assert checkio([3, 1, 2, 5, 3]) == 3, "Not sorted list"
    assert checkio([1, 300, 2, 200, 1]) == 2, "It's not an average"
    assert checkio([3, 6, 20, 99, 10, 15]) == 12.5, "Even length"
    print("Start the long test")
    assert checkio(list(range(1000000))) == 499999.5, "Long."
    print("The local tests are done.")