title: writeToFile message doesn't work or produce a file in the set path
body: <p>Why doesn't this create a text file on my desktop? The error description is "null". </p>
  
  <pre><code>    NSString* path = @"/Users/amr/Desktop/test5.txt";
      NSError* error = nil;
  
  
      NSData* data = [NSData dataWithContentsOfFile:@"hello"];
      [data writeToFile:path options:NSDataWritingAtomic error:nil];
  
      NSLog(@"the error is %@",[error localizedDescription]);
  </code></pre>