

          keylget listvar key [retvar | {}]
               Return the value associated with the key out of keyed
               list in the variable listvar.  If retvar is not
               specified, then the value will be returned as the
               result of the command.  If key is not found in the
               list, an error will result.  If retvar is specified and
               key is in the list, then the value is returned in the
               variable retvar and the command returns one. If key is
               not in the list, the command will return 0 and retvar
               will be unchanged.  If {} is specified for retvar, the
               value is not returned, only the presence of the key is
               determined.
