I have heard it claimed (in personal conversations) that when the IAEA wishes to make an inspection/visit to an Iranian nuclear facility, it is required to announce its visit a good number of days in advance.
Is that ever the case at all? If so, is it typically the case? And - is it anchored in provisions of the JCPOA or just a rapport which developed somehow?
Note: In your answer, please make it clear whether you're describing the period while the JCPOA was fully in effect and the last couple of years after Trump pulled out of the agreement and Iran started reducing its commitment in reciprocation.