transaction/period.js
function (catTail) {
        var cats = kb.findSubClassesNT(ns.qu('Transaction'))
        for (var cat in cats) {
          if (cats.hasOwnProperty(cat)) {
            if (cat.slice(1, -1).split('#')[1] === catTail) {
              return kb.sym(cat.slice(1, -1))
            }
          };
        };
        return null
      }
function (catTail) {
        var cats = kb.findSubClassesNT(ns.qu('Transaction'))
        for (var cat in cats) {
          if (cats.hasOwnProperty(cat)) {
            if (cat.slice(1, -1).split('#')[1] === catTail) {
              return kb.sym(cat.slice(1, -1))
            }
          };
        };
        return null
      }
///////////////  Check some categories of transaction for having given fields