562B.3  Supplementary principles of law applicable.
  Unless displaced by the provisions of this chapter, the principles of law and equity, 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 supplement its provisions.
[C79, 81, §562B.3]