def _get_dihedral_rb_torsion_key(dihedral, epsilon_conversion_factor):
    """Get the dihedral_type key for a Ryckaert-Bellemans (RB) dihedrals/torsions

    Parameters
    ----------
    dihedral : parmed.topologyobjects.Dihedral
        The dihedral information from the parmed.topologyobjects.Angle
    epsilon_conversion_factor : float or int
        The epsilon conversion factor

    Returns
    ----------
    tuple, (dihed_type_RB_c0,  dihed_type_RB_c1, dihed_type_RB_c2, dihed_type_RB_c3, dihed_type_RB_c4,
        dihed_type_RB_c5, dihed_type_scee, dihed_type_scnb, dihed_atom_1_type, dihed_atom_2_type,
        dihed_atom_3_type, dihed_atom_4_type, dihed_atom_1_res_type, dihed_atom_2_res_type,
        dihed_atom_3_res_type,  dihed_atom_4_res_type)
        dihed_type_RB_c0 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C0 constant.
        dihed_type_RB_c1 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C1 constant.
        dihed_type_RB_c2 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C2 constant.
        dihed_type_RB_c3 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C3 constant.
        dihed_type_RB_c4 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C4 constant.
        dihed_type_RB_c5 : float
            Ryckaert-Bellemans (RB) dihedrals/torsions C5 constant.
        dihed_type_scee : float, default = 1.0
            The 1-4 electrostatic scaling factor
        dihed_type_scnb : float, default = 1.0
            The 1-4 Lennard-Jones scaling factor.
        dihed_atom_1_type : str
            The atom type for atom number 1 in the dihedral
        dihed_atom_2_type : str
            The atom type for atom number 2 in the dihedral
        dihed_atom_3_type : str
            The atom type for atom number 3 in the dihedral
        dihed_atom_4_type : str
            The atom type for atom number 4 in the dihedral
        dihed_atom_1_res_type : str
            The residue name for atom number 1 in the dihedral
        dihed_atom_2_res_type : str
            The residue name for atom number 2 in the dihedral
        dihed_atom_3_res_type : str
            The residue name for atom number 3 in the dihedral
        dihed_atom_4_res_type : str
            The residue name for atom number 4 in the dihedral
    """

    lj_unit = 1 / epsilon_conversion_factor

    dihed_type_RB_c0 = round(dihedral.type.c0 * lj_unit, 8)
    dihed_type_RB_c1 = round(dihedral.type.c1 * lj_unit, 8)
    dihed_type_RB_c2 = round(dihedral.type.c2 * lj_unit, 8)
    dihed_type_RB_c3 = round(dihedral.type.c3 * lj_unit, 8)
    dihed_type_RB_c4 = round(dihedral.type.c4 * lj_unit, 8)
    dihed_type_RB_c5 = round(dihedral.type.c5 * lj_unit, 8)

    dihed_type_scee = round(dihedral.type.scee, 4)
    dihed_type_scnb = round(dihedral.type.scnb, 4)

    dihed_atom_1_type = dihedral.atom1.type
    dihed_atom_2_type = dihedral.atom2.type
    dihed_atom_3_type = dihedral.atom3.type
    dihed_atom_4_type = dihedral.atom4.type

    dihed_atom_1_res_type = dihedral.atom1.residue.name
    dihed_atom_2_res_type = dihedral.atom2.residue.name
    dihed_atom_3_res_type = dihedral.atom3.residue.name
    dihed_atom_4_res_type = dihedral.atom4.residue.name

    return (
        dihed_type_RB_c0,
        dihed_type_RB_c1,
        dihed_type_RB_c2,
        dihed_type_RB_c3,
        dihed_type_RB_c4,
        dihed_type_RB_c5,
        dihed_type_scee,
        dihed_type_scnb,
        dihed_atom_1_type,
        dihed_atom_2_type,
        dihed_atom_3_type,
        dihed_atom_4_type,
        dihed_atom_1_res_type,
        dihed_atom_2_res_type,
        dihed_atom_3_res_type,
        dihed_atom_4_res_type,
    )