@classmethod
def is_track_file(classname, filename):
    """Is the file a type PyTopo recognizes as a track file?
           But it's more efficient to call read_track_file() wrapped in a try
           to avoid checking the extension twice.
        """
    ext = classname.lowerext(filename)
    for mapper in classname.mappers:
        if ext in mapper[0]:
            return True
    return False
