def read_input_file(file, fallback_encoding):
    """return contents of the specified file as a list or None if it can't be read
    """
    try:
        with file.open() as f_in:
            return f_in.readlines()
    except UnicodeDecodeError:
        try:
            with file.open("r", encoding=fallback_encoding) as f_in:
                return f_in.readlines()
        except UnicodeDecodeError:
            return None