Шпионы

def povt(x):
    s = []
    for i in x:
        ii = i.lower()
        if ii in s:
            return False
        if ii not in s:
            s.append(ii)
    return True


f1 = open('spies.txt', 'r')
f2 = open('suspicions.txt', 'w')
for i in f1:
    for ii in i.split():
        if povt(ii):
            f2.write(ii + ' ')
    f2.write('\n')
f1.close()
f2.close()