title: Python Check dictionary object for correct keys throw custom exception
body: <p>So I have a method that takes a dictionary object as a parameter. I want to check over the dictionary to make sure it has all the correct keys and if not throw a custom exception. The code I have so far works but I am thinking there might be a better way. (Using Python 2.7)</p>
  
  <pre><code>def my_method(temp_dict):
      #this is the part that looks messy and I would like to improve
      if "key" not in temp_dict:
          raise CustomException("Message key is missing from dict")
      if "key1" not in temp_dict:
          raise CustomException("Message key1 is missing from dict")
      if "key2" not in temp_dict:
          raise CustomException("Message key2 is missing from dict")
      if "key3" not in temp_dict:
          raise CustomException("Message key3 is missing from dict")
  
  my_dict = {}
  my_dict["key"] = "test"
  my_dict["key1"] = "test"
  my_dict["key2"] = "test"
  
  my_method(my_dict)
  </code></pre>
  
  <p>Link to Python Fiddle <a href="http://pythonfiddle.com/checking-dict-for-keys" rel="nofollow noreferrer">Link</a></p>