562A.3  Supplementary principles of law applicable.
  Unless displaced by the provisions of this chapter, the principles of law and equity in this state, including the law relating to capacity to contract, mutuality of obligations, principal and agent, real property, public health, safety and fire prevention, estoppel, fraud, misrepresentation, duress, coercion, mistake, bankruptcy, or other validating or invalidating cause, shall supplement its provisions.
[C79, 81, §562A.3]