Section 6618 - Suits to recover assessments(a) An assessment corporation may maintain a civil action against any member or former member of such corporation for the unpaid amount of any extraordinary or post assessment lawfully levied against him, or against any former member of such corporation for the earned portion of any advance assessment which he has failed to pay.(b) In any such action the corporation may recover, in addition to such sum or sums, legal interest thereon and the amount of any penalty imposed by such corporation's by-laws for failure to pay such assessments; but no such corporation shall provide in its by-laws for such a penalty in excess of fifty percent of such an assessment.