No action for possession of real property shall be
maintained if the dominant purpose in bringing the action is reprisal.
Also, no such action shall be maintained if the plaintiff attempted
to increase the tenant's obligation under the lease as a reprisal
and the tenant's failure to perform such additional obligation is
a material reason for bringing such action. Also, no such action shall
be maintained on the ground of refusal to pay rent if the plaintiff
threatened to or did decrease his obligations under the lease as such
a reprisal, and the tenant refused to pay rent because of the reprisal.