Is there any built in library for linear kernel in scikit learn like RBF, SE?

I want to multiply linear kernel with RBF for a dataset but finding no way to implement linear kernel. How can I implement the linear kernel here.For example RBF, SE can be used in Scikit learn like :

k2 = 2.0**2 * RBF(length_scale=100.0)  k_exp = ExpSineSquared(length_scale=1.0, periodicity=1.0,                       periodicity_bounds="fixed")