def IsValidFilename(filename):
    """IsValidFilename(filename) -> bool
    
    Determines if the given filename is a valid filename. It is invalid if it
    contains any of the characters found in the string return by 
    GetInvalidString().
    
    arguments:
        filename
            string corresponding to the filename to check.
    
    returns:
        bool corresponding to whether the given filename is valid.
    
    """
    return ((filename.find("\\") == -1) and (filename.find("/") == -1) and
            (filename.find(":") == -1) and (filename.find("*") == -1) and
            (filename.find("?") == -1) and (filename.find("\"") == -1) and
            (filename.find("<") == -1) and (filename.find(">") == -1) and
            (filename.find("|") == -1))