input: Write a function to convert a list of JSON objects to a CSV file.
  assert convert_json_to_csv([{"name": "Alice", "age": 30, "country": "USA"}, {"name": "Bob", "age": 25, "country": "UK"}], 'output.csv')==None
  assert open('output.csv').readlines()==['Name,Age,Country\n', 'Alice,30,USA\n', 'Bob,25,UK\n']
output: def convert_json_to_csv(json_list, csv_file):
      import csv
  
      if not json_list:
          return
      
      keys = json_list[0].keys()
      with open(csv_file, 'w', newline='') as output_file:
          dict_writer = csv.DictWriter(output_file, fieldnames=keys)
          dict_writer.writeheader()
          dict_writer.writerows(json_list)