1a5f9918aSopenharmony_ci# sets are represented as a 2a5f9918aSopenharmony_ci# mapping where each key is 3a5f9918aSopenharmony_ci# associated with the empty string 4a5f9918aSopenharmony_ci--- !!set 5a5f9918aSopenharmony_ci? Mark McGwire 6a5f9918aSopenharmony_ci? Sammy Sosa 7a5f9918aSopenharmony_ci? Ken Griff 8