What is the applicable limitation period for bringing a claim for damages arising out of a latent defect in the development of real property?

4 Even were we to entertain arguendo the premise that Code of Civil Procedure section 337.15 provides the applicable limitation period, the finding of actual knowledge on the part of appellants precludes them from here demanding arbitration. The 10-year period set forth in Code of Civil Procedure section 337.15 is not absolute, but onlysets the outer limit within which suit must be brought. "Section 337.15, read together with Code of Civil Procedure sections 337 ... enacts ... a two-step limitation: actions founded upon a latent defect in the development of real property must be filed within ... four years of discovery, ... but in any case within ten years of the date of substantial completion of the improvement." (Regents of University of California v. Hartford Acc. & Indem. Co. (1978) 21 Cal.3d 624, 641, 147 Cal.Rptr. 486, 581 P.2d 197.)