docs: public boolean fnameExists(final String fname) {
          boolean rslt = false; // default
          try {
              final ITenant tenant = getTenantByFName(fname);
              rslt = tenant != null;
          } catch (IllegalArgumentException iae) {
              // This exception is completely fine;  it simply
              // means there is no tenant with this fname.
              rslt = false;
          }
          return rslt;
      }