title: Filtering NSDictionary with predicate
body: <p>I am using a NSDictionary that itself contains dictionaries some keys and its values.The format is like ,</p>
  
  <pre><code>{
  
  "1" = {
          "key1" = "ss",
            "key2" = "rr",
            "name" = "nm"
       },
  "2" = {
             "key1" = "tt",
            "key2" = "vv",
             "name" = "gf"
       },
  "3" = {
             "key1" = "nm",
            "key2" = "vv",
             "name" = "gf"
       },
  "4" = {
             "key1" = "tt",
            "key2" = "vv",
            "name" = "gf"
       },
  }
  </code></pre>
  
  <p>I need to filter with the case that key1 should be "tt" and key2 should "vv" using NSPredicate.</p>