def basis(x):
    """
    Return the fixed basis of ``x``.

    EXAMPLES::

        sage: V = VectorSpace(QQ,3)
        sage: S = V.subspace([[1,2,0],[2,2,-1]])
        sage: basis(S)
        [
        (1, 0, -1),
        (0, 1, 1/2)
        ]
    """
    return x.basis()