In Life v. County of Los Angeles (1991) 227 Cal. App. 3d 894, the plaintiff contended that the County of Los Angeles was estopped to assert the claims statute because an employee of the county facility medical center advised the plaintiff's attorney "to file a claim directly with the hospital's 'legal department.'" In response, the court stated: "The argument need not detain us.Estoppel requires, inter alia, a representation or concealment of material facts to a party ignorant, 'actually and permissibly,' of the truth. (11 Witkin, Summary of Cal. Law (9th ed. 1990) Equity, 177, p. 859.) In view of section 915 and applicable case law, it cannot be maintained that attorney for plaintiff reasonably could rely on the advice of a medical records clerk to file a claim with the hospital's legal department, so as to estop the County." (Life v. County of Los Angeles, supra, 227 Cal. App. 3d 894, 902.)