iOS – Corrigindo chaves não entre aspas na string JSON

+ (NSString *)fixJSON:(NSString *)s {
 NSRegularExpression *regexp = [NSRegularExpression regularExpressionWithPattern:@"[{,]\s*(\w+)\s*:"
 options:0
 error:NULL];
 NSMutableString *b = [NSMutableString stringWithCapacity:([s length] * 1.1)];
 __block NSUInteger offset = 0;
 [regexp enumerateMatchesInString:s
 options:0
 range:NSMakeRange(0, [s length])
 usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
 NSRange r = [result rangeAtIndex:1];
 [b appendString:[s substringWithRange:NSMakeRange(offset, r.location - offset)]];
 [b appendString:@"""];
 [b appendString:[s substringWithRange:r]];
 [b appendString:@""""""];
 offset = r.location + r.length;
 }];
 [b appendString:[s substringWithRange:NSMakeRange(offset