What is the test for obtaining a personal deficiency judgment against a lender who has a mortgage secured by a deed of trust?

(1) Code of Civil Procedure section 726, subdivision (a), which allows only one action and one form of action for the recovery of a debt or enforcement of a right secured by a mortgage or deed of trust. The practical consequence of this limitation is that a creditor may not obtain a personal deficiency judgment against a debtor without first exhausting the security. (Pacific Valley Bank v. Schwenke (1987) 189 Cal.App.3d 134, 140, 234 Cal.Rptr. 298.)