code: public PagedList<KeyItem> listKeys(final String vaultBaseUrl, final Integer maxresults) {
          return getKeys(vaultBaseUrl, maxresults);
      }
docs: List keys in the specified vault.
  
  @param vaultBaseUrl
  The vault name, e.g. https://myvault.vault.azure.net
  @param maxresults
  Maximum number of results to return in a page. If not specified
  the service will return up to 25 results.
  @return the PagedList&lt;KeyItem&gt; if successful.