In Zager v. Chester Community Charter School, 594 Pa. 166, 173, 934 A.2d 1227, 1231 (2007), the issue was whether a charter school was an agency within the meaning of the previous Right-to-Know Act (Act) that defined an agency as, among other things, an "organization created by or pursuant to a statute which declares in substance that such organization performs or has for its purpose the performance of an essential governmental function." Former Section 2 of the Act, 65 P.S. 66.2. It found that an agency performed an "essential governmental function" where "the performing entity must be either statutorily identified as providing an essential service or provide a service which is constitutionally mandated or indisputably necessary to continued existence of the Commonwealth." Zager, 594 Pa. at 173, 934 A.2d at 1231.