Joined Cases T-389/19 to T-394/19, T-397/19, T-398/19, T-403/19, T-404/19, T-406/19, T-407/19, T-409/19 to T-414/19, T-416/19 to T-418/19, T-420/19 to T-422/19, T-425/19 to T-427/19, T-429/19 to T-432/19, T-435/19, T-436/19, T-438/19 to T-442/19, T-444/19 to T-446/19, T-448/19, T-450/19 to T-454/19, T-463/19 and T-465/19: Judgment of the General Court of 15 October 2020 — Coppo Gavazzi and Others v Parliament (Institutional law — Single statute for Members of the European Parliament — Members of the European Parliament elected in Italian constituencies — Adoption by the Ufficio di Presidenza della Camera dei deputati (Office of the President of the Italian Chamber of Deputies, Italy) of Decision No 14/2018, on pensions — Change in the amount of the pensions of members of the Italian national parliament — Consequential change by the European Parliament in the amount of the pensions of certain former Members of the European Parliament elected in Italy — Competence of the authority which adopted the measure — Obligation to state reasons — Acquired rights — Legal certainty — Legitimate expectations — Right to property — Proportionality — Equal treatment)