In connection with the issuance of bonds under any law permitting the issuance of refunding bonds, a local agency may declare the proceeds of such refunding bonds to be a revenue producing public facility, including an enterprise under the Revenue Bond Law of 1941, or may declare such proceeds to be part of such revenue producing public facility or enterprise or may otherwise declare such proceeds to be held, in whole or in part, and for such time as the local agency may deem advisable, in trust for the protection of holders of the bonds or of the refunding bonds.