input: Write a python function to parse a json string and pretty print it.
  assert pretty_print_json("{\"name\":\"John Doe\",\"age\":30}") == '{\n    "age": 30,\n    "name": "John Doe"\n}'
  assert pretty_print_json("{\"city\":\"New York\",\"population\":8000000}") == '{\n    "city": "New York",\n    "population": 8000000\n}'
  assert pretty_print_json("{\"fruit\":\"Apple\",\"color\":\"Red\"}") == '{\n    "color": "Red",\n    "fruit": "Apple"\n}'
output: import json
  
  def pretty_print_json(json_string):
      parsed = json.loads(json_string)
      return json.dumps(parsed, indent=4, sort_keys=True)