How have courts interpreted contract language in the context of a class action waiver?

Here, the relevant contract language, which the superior court did not address, is the nonseverability clause within paragraph No. 4. Immediately after the class action waiver, this clause provides: Notwithstanding any other clause in this Agreement, the preceding sentence shall not be severable from this Agreement in any case in which the dispute to be arbitrated is brought as a class, collective or representative action. (Italics added.) The fundamental rule is that interpretation of ... any contract ... is governed by the mutual intent of the parties at the time they form the contract. [Citation.] The parties' intent is found, if possible, solely in the contract's written provisions. [Citation.] The clear and explicit meaning of these provisions, interpreted in their ordinary and popular sense, unless used by the parties in a technical sense or a special meaning is given to them by usage [citation], controls judicial interpretation. [Citation.] If a layperson would give the contract language an unambiguous meaning, we apply that meaning.' (Nelsen v. Legacy Partners Residential, Inc. (2012) 207 Cal.App.4th 1115, 1129, [144 Cal.Rptr.3d 198].) The parties' expressed objective intent, not their unexpressed subjective intent, governs. (In re Tobacco Cases I (2010) 186 Cal.App.4th 42, 47, [111 Cal.Rptr.3d 313].)