title: Add one property to json in python
body: <p>I have the below json, I want to add one more property:</p>
  
  <pre><code>[   {
          "A": 1,
          "B": "str"
      },
      {
          "A": 2,
          "B": "str2"
      },
      {
          "A": 3,
          "B": "str3"
      }
  ]
  </code></pre>
  
  <p>So I want something like this:</p>
  
  <pre><code>[   {
          "A": 1,
          "B": "str",
          "C": "X"
      },
      {
          "A": 2,
          "B": "str2",
          "C": "X"
      },
      {
          "A": 3,
          "B": "str3",
          "C": "X"
      }
  ]
  </code></pre>
  
  <p>What is the best way to do this?</p>