def header(table):
    """
    Return the header row for the given table. E.g.::

        >>> import petl as etl
        >>> table = [['foo', 'bar'], ['a', 1], ['b', 2]]
        >>> etl.header(table)
        ('foo', 'bar')

    Note that the header row will always be returned as a tuple, regardless
    of what the underlying data are.

    """

    it = iter(table)
    return tuple(next(it))