code: function(term) {
      try {
          if(term == null) {
              return "";
          } if(term.token==='uri') {
              return "u"+term.value;
          } else if(term.token === 'blank') {
              return "b"+term.value;
          } else if(term.token === 'literal') {
              var l = "l"+term.value;
              l = l + (term.type || "");
              l = l + (term.lang || "");
  
              return l;
          }
      } catch(e) {
          if(typeof(term) === 'object') {
              var key = "";
              for(p in term) {
                  key = key + p + term[p];
              }
  
              return key;
          }
          return term;
      }
  }
docs: Function that generates a hash key for a bound term.
  @param term
  @returns {*}