code: public String mapNamespace(String ns, SiteInfo targetWiki) throws Exception {
      Map<String, Ns> sourceMap = this.getNamespaces();
      Map<Integer, Ns> targetMap = targetWiki.getNamespacesById();
      Ns sourceNs = sourceMap.get(ns);
      if (sourceNs == null) {
        if (debug)
          LOGGER.log(Level.WARNING, "can not map unknown namespace " + ns);
        return ns;
      }
      Ns targetNs = targetMap.get(sourceNs.getId());
      if (targetNs == null) {
        if (debug)
          LOGGER.log(
              Level.WARNING,
              "missing namespace " + sourceNs.getValue() + " id:"
                  + sourceNs.getId() + " canonical:" + sourceNs.getCanonical());
        return ns;
      }
      return targetNs.getValue();
    }
docs: map the given namespace to the target wiki
  
  @param ns
  @param targetWiki
  @return the namespace name for the target wiki
  @throws Exception