title: Python replace values in unknown structure JSON file
body: <p>Say that I have a JSON file whose structure is either unknown or may change overtime - I want to replace all values of "REPLACE_ME" with a string of my choice in Python.</p>
  
  <p>Everything I have found assumes I know the structure. For example, I can read the JSON in with <code>json.load</code> and walk through the dictionary to do replacements then write it back. This assumes I know Key names, structure, etc.</p>
  
  <p>How can I replace ALL of a given string value in a JSON file with something else?</p>