Md. Code, Courts and Judicial Proceedings § 3–406

Any person interested under a deed, will, trust, land patent, written contract, or other writing constituting a contract, or whose rights, status, or other legal relations are affected by a statute, municipal ordinance, administrative rule or regulation, contract, or franchise, may have determined any question of construction or validity arising under the instrument, statute, ordinance, administrative rule or regulation, land patent, contract, or franchise and obtain a declaration of rights, status, or other legal relations under it.