code: @Nonnull
    public static <KEYTYPE, VALUETYPE> String getImploded (@Nonnull final String sSepOuter,
                                                           @Nonnull final String sSepInner,
                                                           @Nullable final Map <KEYTYPE, VALUETYPE> aElements)
    {
      return getImplodedMapped (sSepOuter, sSepInner, aElements, String::valueOf, String::valueOf);
    }
docs: Get a concatenated String from all elements of the passed map, separated by
  the specified separator strings.
  
  @param sSepOuter
  The separator to use for separating the map entries. May not be
  <code>null</code>.
  @param sSepInner
  The separator to use for separating the key from the value. May not be
  <code>null</code>.
  @param aElements
  The map to convert. May be <code>null</code> or empty.
  @return The concatenated string.
  @param <KEYTYPE>
  Map key type
  @param <VALUETYPE>
  Map value type