title: map the dictionary and list of dictionary,finally update the list of dictionary after mapping
body: <pre><code>req_dict =  {
  1: {'f1': 'name', 'f2': 'age', 'f3': 'class'}, 
  2: {'f1': 'company', 'f2': 'salary', 'f3': 'age', 'f4': 'class'}, 
  3: {'f1': 'Feature', 'f2': 'sum', 'f3': 'diff', 'f4': 'multiply', 'f5': 'div'}
  }
  
  level_input =  [
  {3: {'sum': 'NONE', 'diff': 'yes', 'multiply': 'NONE', 'div': 'NONE', 'FEATURE': 'Maths'}}, 
  {2: {'COMPANY': 'NONE', 'SALARY': 'Pass', 'AGE': 'NONE', 'CLASS': 'unknown'}},
  {1: {'NAME': 'Pass', 'AGE': 'NONE', 'CLASS': '3'}}
  ]
  </code></pre>
  
  <p>i need output as</p>
  
  <pre><code>updated_level_input = [
  {3: {'f1': 'Maths', 'f2': 'none', 'f3': 'yes', 'f4': 'NONE', 'f5': 'NONE'}}, 
  {2: {'f1': 'NONE', 'f2': 'Pass', 'f3': 'NONE', 'f4': 'unknown'}}, 
  {1: {'f1': 'Pass', 'f2': 'NONE', 'f3': '3'}}
  ]
  </code></pre>
  
  <p>i tried below code</p>
  
  <pre><code>level_dict = {}
      [level_dict.update(key) for key in levels_input]
  
      for key in req_dict:
          #print key
          for dict_key in req_dict[key]:
              print dict_key          
              searchKey = req_dict[key][dict_key]
              print searchKey.upper()         
              if searchKey.upper() in level_dict[key].keys():
                  #print level_dict[key].keys()
                  req_dict[key][dict_key] = req_dict[key][searchKey.upper()]                  
              else:
                  req_dict[key][dict_key] = level_dict[key][searchKey]
  print [req_dict]
  </code></pre>
  
  <p>but i get the output as</p>
  
  <pre><code>updated_level_input=[
  {3: {'f1': 'Maths', 'f2': 'none', 'f3': 'yes', 'f4': 'NONE', 'f5': 'NONE'}, 
  2: {'f1': 'NONE', 'f2': 'Pass', 'f3': 'NONE', 'f4': 'unknown'}, 
  1: {'f1': 'Pass', 'f2': 'NONE', 'f3': '3'}}
  ]
  </code></pre>
  
  <p>basically i tried to modify <code>req_dict</code> input,which is not <code>correct.i</code> should modify <code>level_input</code> list</p>