<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def upload_file(self, filename, file_type=FILE_TYPE_FREESURFER_DIRECTORY):
 """Create an anatomy object on local disk from the given file. Currently, only Freesurfer anatomy directories are supported. Expects a tar file. Parameters filename : string Name of the (uploaded) file file_type : string File type (currently expects FILE_TYPE_FREESURFER_DIRECTORY) Returns ------- SubjectHandle Handle for created subject in database """

        # We currently only support one file type (i.e., FREESURFER_DIRECTORY).
        if file_type != FILE_TYPE_FREESURFER_DIRECTORY:
            raise ValueError('Unsupported file type: ' + file_type)
        return self.upload_freesurfer_archive(filename)