code: public String getStringTag(String key) {
  		Object value = tags.get(key);
  		if (value instanceof String) {
  			return (String) value;
  		}
  		return null;
  	}
docs: This method returns the tag value, associated with the supplied key, if it exists and has a {@link String} type.
  
  @param key The tag key
  @return The value, if exists and is a {@link String} type, otherwise null