def validDBMLFile(s):
    """
    Return a boolean indicating whether passed string has valid `.dbml` file extension. Case-sensitive (i.e. `.DBML` not accepted).

    Parameters:
    s (str): name of file.

    Returns:
    bool: True if s ends with '.dbml', else False.
    """
    if s.endswith('.dbml'):
        return True
    else:
        return False