code: @Nullable
    public static Charset getCharsetFromMimeType (@Nullable final IMimeType aMimeType)
    {
      final String sCharsetName = getCharsetNameFromMimeType (aMimeType);
      return CharsetHelper.getCharsetFromNameOrNull (sCharsetName);
    }
docs: Determine the charset from the provided MIME type.
  
  @param aMimeType
  The MIME type to query. May be <code>null</code>.
  @return <code>null</code> if no MIME type was provided or if the MIME type
  does not contain a "charset" parameter or if the provided charset
  name is invalid.