       keylset listvar key value ?key2 value2 ...?
              Set  the  value  associated  with key, in the keyed
              list contained in the variable listvar,  to  value.
              If  listvar does not exists, it is created.  If key
              is not currently in the list, it will be added.  If
              it  already  exists,  value  replaces  the existing
              value.  Multiple keywords and values may be  speci-
              fied, if desired.

              This command is provided by Extended Tcl.
