_StringIsValid() is simple function which checks a string for any of the pre-defined invalid characters. If the string contains none of the invalid characters then it returns True, else it will return False if the string contains any single invalid character. There are similar functions on the forum but they require some knowledge of regular expressions, for example in this function you can define a backslash () without having to do the double-backslash () which is how to escape a backslash in a