56In that regard, it should be recalled that, according to Article 84(1) of the Rules of Procedure, no new plea in law may be introduced in the course of proceedings unless it is based on matters of law or fact which have come to light in the course of the procedure. However, a plea which constitutes an amplification of a plea previously made, either expressly or by implication, in the original application and is closely linked to it must be declared admissible. To be regarded as an amplification of a plea or a head of claim previously advanced, a new line of argumentation must, in relation to the pleas or heads of claim initially set out in the application, present a sufficiently close connection with the pleas or heads of claim initially put forward in order to be considered as forming part of the normal evolution of debate in proceedings before the Court (see judgment of 20 November 2017, Petrov and Others v Parliament, T‑452/15, EU:T:2017:822, paragraph 46 and the case-law cited).