def archive_to_fits(ar_file, extension="fits", container="/pawsey/mwa/singularity/dspsr/dspsr.sif"):
    """Returns bash commands to turn an arhive file to a fits file"""
    container_launch = f"singularity exec -e {container}"
    pam_cmd = f"{container_launch} pam -a PSRFITS"
    pam_cmd += f" -e {extension}"
    pam_cmd += f" {ar_file}"
    return pam_cmd