title: How to check JSON format validation?
body: <p>My program gets a JSON file that has an information for service.<br/>
  Before run the service program, I want to check if the JSON file is valide(Only check whether all necessary keys exist).<br/>
  Below is the standard(necessary datas) JSON format for this program:</p>
  
  <pre><code>{
      "service" : "Some Service Name"
      "customer" : {
          "lastName" : "Kim",
          "firstName" : "Bingbong",
          "age" : "99",
      }
  }
  </code></pre>
  
  <p>Now I am checking the JSON file validation like this:</p>
  
  <pre><code>import json
  
  def is_valid(json_file):
  
      json_data = json.load(open('data.json'))
  
      if json_data.get('service') == None:
          return False
      if json_data.get('customer').get('lastName') == None:
          return False
      if json_data.get('customer').get('firstName') == None:
          return False
      if json_data.get('customer').get('age') == None:
          return False
  
      return True
  </code></pre>
  
  <p>Actually, the JSON standard format has more than 20 keys. Is there any other way to check the JSON format?</p>