title: How to save data into JSON to specified keys? For Python 3.7
body: <p>I have little script on python and I want receive results into JSON file.</p>
  <p>I prepared already JSON keys with names of tests.</p>
  <p>It looks like this one:</p>
  <pre><code>{
      &quot;key1&quot; : &quot;&quot;
      &quot;key2&quot; : &quot;&quot;
      &quot;key3&quot; : &quot;&quot;
  
  }
  </code></pre>
  <p>And now I want to save results (usual str (after if else tests)) as value into specified key.</p>
  <p>How can I perform it?</p>
  <p>Thank you!</p>
  <p>EDIT: not create dictionary, not take FROM JSON. Only write to specified key.</p>
  <p>Like (by script, of course):</p>
  <p>&quot;Write 'my_str' to My_json[My_key]&quot;</p>