<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def filesystem_repository(_context, name=None, make_default=False, aggregate_class=None, repository_class=None, directory=None, content_type=None):
 """ Directive for registering a file-system based repository. """

    cnf = {}
    if not directory is None:
        cnf['directory'] = directory
    if not content_type is None:
        cnf['content_type'] = content_type
    _repository(_context, name, make_default,
                aggregate_class, repository_class,
                REPOSITORY_TYPES.FILE_SYSTEM, 'add_filesystem_repository',
                cnf)