If the writing does not purport to contain all the stipulations of the contract, parol evidence shall be admissible to prove other portions thereof not inconsistent with the writing; collateral undertakings between parties of the same part among themselves would not properly be looked for in the writing. History. Code 1981, § 24-3-2, enacted by Ga. L. 2011, p. 99, § 2/HB 24.