def eval_f(f, xs):
    """Takes a function f = f(x) and a list xs of values that should be used as arguments for f.
     The function eval_f should apply the function f subsequently to every value x in xs, and
    return a list fs of function values. I.e. for an input argument xs=[x0, x1, x2,..., xn] the
    function eval_f(f, xs) should return [f(x0), f(x1), f(x2), ..., f(xn)]."""

    return [f(x) for x in xs]
    # alternatively: return list(map(f, xs))