def func_eq_all(parser, x, *args):
    """
    Return True if all string are equal.
    $eq_all(a,b,c ...) is functionally equivalent to $and($eq(a,b),$eq(a,c) ...)
    Example: $if($eq_all(%albumartist%,%artist%,Justin Bieber),$set(engineer,Meat Loaf))
    """
    for i in args:
        if x != i:
            return ''
    return '1'
