-returnUnique: aString {
	int i;
	id newString = [[NSMutableString alloc] init];
	id charSet = [[NSMutableCharacterSet alloc] init];
	for(i=0; i<[aString length]; i++) {
		char c = [aString characterAtIndex:i];
		if(![charSet characterIsMember: c]) {
			[charSet addCharactersInString:[NSString stringWithFormat:@"%c", c]];
			[newString appendFormat:@"%c", c];
		}
	}
	return newString;
}