// construct mutation string
prefix = "sequence_";
chain = "A";
res = toupper string knime_GetFlowVariable 'Residue';
uid = swrite['{}', knime_GetFlowVariable 'UID'];
mut1 = cat[prefix, chain, " ", res, " ", uid, " ", "A"];
chain = "B";
mut2 = cat[prefix, chain, " ", res, " ", uid, " ", "A"];
mutstr = cat[mut1, "\n", mut2];
knime_SetFlowVariable['mutstr', 'string', mutstr];
result = mutstr;