title: python 3: How to rearrange dictionaries in list by new variable without adding new key and value
body: <p>I want to rearrange dictionaries with new variable which is newly defined with existing variables. 
  For example,</p>
  
  <pre><code>security_info = [{'date': '19.04.15', 'price': 785000, 'trade': 79620},
                   {'date': '19.04.16', 'price': 785000, 'trade': 68203},
                   {'date': '19.04.17', 'price': 754000, 'trade': 165929},
                   {'date': '19.04.18', 'price': 779000, 'trade': 94462},
                   {'date': '19.04.19', 'price': 770000, 'trade': 76814},
                   {'date': '19.04.22', 'price': 774000, 'trade': 58079},
                   {'date': '19.04.23', 'price': 775000, 'trade': 79128},
                   {'date': '19.04.24', 'price': 771000, 'trade': 61650},
                   {'date': '19.04.25', 'price': 757000, 'trade': 111805},
                   {'date': '19.04.26', 'price': 764000, 'trade': 68237}]
  </code></pre>
  
  <p>I want rearrange this list by 'net return', which is defined by 'price today/price yesterday *100' (of course 'net return' of first date does not exist). 
  But I don't want to solve this by adding new key and value. </p>
  
  <p>Thanks. </p>