simple_cycpep_predict - Design mode - The base name "ARG" was added more than once

Hello,

I am using simple_cycpep_predict in design mode to find derivatives of a peptide for disulfide cyclization. For the -cyclic_peptide:allowed_residues_by_position option I am using the following file:

DEFAULT ILE LEU ARG TRP SER ARG LYS LEU PRO CYS VAL SER
1 ILE                 # Only ILE at this position.
2 ILE LEU VAL         # Only branched, small, hydrophobic residues at this position.
3 ARG LYS             # Only positively-charged residues at this position.
4 TRP PHE TYR CYS     # Only hydrophobic, bulky, slightly polar, or CYS residues at this position.
5 SER CYS             # CYS in this position
6 ARG LYS GLU ASP CYS # Only negative, positive residues, or CYS at this position.

But I get the following error:

[FILE]: src/core/pack/task/ResfileReader.cc
[LINE]: 708
[START_MESSAGE]
[ ERROR ] UtilityExitException
ERROR: Error in core::pack::task::PIKAA::add_base_name_to_keep(): The base name "ARG" was added more than once.

[END_MESSAGE]
[END_CRASH_REPORT]

Is there anything wrong with the format of the residues file?

Best