input: Write a python function to parse command line arguments for a base directory with model files.
  assert parse_arguments(['--basedir', '/path/to/base']) == '/path/to/base'
  assert parse_arguments([]) == base
output: def parse_arguments(args):
      import argparse
      parser = argparse.ArgumentParser(description='Parse command line arguments for a base directory with model files.')
      parser.add_argument('--basedir', type=str, default='base', help='Base directory with model files')
      parsed_args = parser.parse_args(args)
      return parsed_args.basedir