def raise_error(msg, line, i, start_line):
    """ raise error when reading line

    Parameters
    ----------
    msg: str
    line: str
    i: int
    start_line: int

    Returns
    -------

    """
    raise IOError('{0}, for line #{1}: {2}'.format(msg, i + 1 + start_line,
        line.strip()))
