i do not know the wrong with my code !!

#Write function called alter_list. alter_list should have

#two parameters: a list of strings and a list of integers.

#

#The list of integers will represent indices for the list of

#strings. alter_list should alter the capitalization of all

#the words at the designated indices. If the word was all

#capitals, it should become all lower case. If it was all

#lower case, it should become all capitals. You may assume

#that the words will already be all-caps or all-lower case.

#

#For example:

#

# string_list = ["hello", "WORLD", "HOW", "are", "you"]

# index_list = [0, 2]

# alter_list(string_list, index_list) ->

#["HELLO", "WORLD", "how", "are", "you"]

#

#After calling alter_list, the strings at indices 0 and 2

#have switched their capitalization.

#

#Note that it may be the case that the same index is present

#in the second twice. If this happens, you should switch the

#text at that index twice. For example:

#

# string_list = ["hello", "WORLD", "HOW", "are", "you"]

# index_list = [0, 2, 2]

# alter_list(string_list, index_list) ->

#["HELLO", "WORLD", "HOW", "are", "you"]

#

#2 is in index_list twice, so the string at index 2 is

#switched twice: capitals to lower case, then back to

#capitals.

#Write function here!

def alter_list(string, integers):

s = []

for i in integers:

x = string[i]

if x.isupper():

ss = x.lower()

s.append(ss)

elif x.islower():

ss = x.upper()

s.append(ss)

return s

#Below are some lines of code that will test your function.

#You can change the value of the variable(s) to test your

#function with different inputs.

#

#If your function works correctly, this will originally

#print:

#["hello", "WORLD", "HOW", "are", "you"]

#["HELLO", "WORLD", "HOW", "are", "you"]

print(alter_list(["hello", "WORLD", "HOW", "are", "you"], [0, 2]))

print(alter_list(["hello", "WORLD", "HOW", "are", "you"], [0, 2, 2]))