def write_key(key, value):
    """Write a `key = value` line in an LTA file.

    Parameters
    ----------
    key : str
    value : int or float or str

    Returns
    -------
    str

    """
    if isinstance(value, (str, int, float)):
        return f'{key} = {value}'
    else:
        return f'{key} = ' + ' '.join([str(v) for v in value])