Vel factory function

def create(max_kl, cg_iters, line_search_iters, cg_damping, entropy_coef, vf_iters, discount_factor,
           gae_lambda=1.0, improvement_acceptance_ratio=0.1, max_grad_norm=0.5):
    """ Vel factory function """
    return TrpoPolicyGradient(
        max_kl, int(cg_iters), int(line_search_iters), cg_damping, entropy_coef, vf_iters,
        discount_factor=discount_factor,
        gae_lambda=gae_lambda,
        improvement_acceptance_ratio=improvement_acceptance_ratio,
        max_grad_norm=max_grad_norm
    )