In City of Santee v. Superior Court (1991) 228 Cal.App.3d 713, the City of Santee contended, as does the City here, that "the exclusive remedy for challenging allegedly improper conditions on a special permit is administrative mandamus, which the permit holder conceded it failed to timely seek. ... The law is firmly established in this state that under these circumstances administrative mandamus constituted the permit holder's exclusive remedy to challenge the propriety of the conditions the City of Santee imposed upon the approval of the ... permit." (Id. at p. 718.) Because the permit holder failed to pursue the exclusive remedy of administrative mandamus, he was estopped from challenging the validity of the permit condition in subsequent proceedings. (Id. at p. 719.)