input: Write a function to load a JSON fixture file, extract properties from it, create Property objects from the properties, save them to the database, and print the number of saved objects to the console. The function should take command line arguments to specify the fixture file and folder. If the fixture file is not explicitly specified, it should default to 'properties.json'. The folder where the fixtures are stored should default to 'models/fixtures'. If the fixture file is empty or does not contain a 'properties' key, the function should handle the error gracefully and return 0.
  
  assert main("/path/to/project") == 3
  assert main("/another/path/to/project") == 5
  assert main("/empty/project") == 0
  assert main("/missing/properties/key") == 0
output: import json
  import os
  
  def main(fixture_file=None, fixture_folder=None):
      if fixture_file is None:
          fixture_file = 'properties.json'
      if fixture_folder is None:
          fixture_folder = 'models/fixtures'
      
      file_path = os.path.join(fixture_folder, fixture_file)
      
      try:
          with open(file_path, 'r') as file:
              data = json.load(file)
              if 'properties' not in data:
                  return 0
              properties = data['properties']
              if not properties:
                  return 0
              
              count = 0
              for prop in properties:
                  # Assuming Property object creation and saving logic here
                  # Property.create(**prop).save()
                  count += 1
              
              return count
      except (FileNotFoundError, json.JSONDecodeError):
          return 0