public Charset getCharset() {
        if( charset == null ) {
            throw new IllegalArgumentException( "No charset is specified for media type " + this );
        }
        return charset;
    }
@return the charset of this media type if one is specified
@throws java.lang.IllegalArgumentException if no charset is specified
jgiven-core/src/main/java/com/tngtech/jgiven/attachment/MediaType.java