Here is a sample argument:

As a preliminary matter, Applicant notes that the effective filing date of the instant
application is July 29, 2015 (which corresponds to the filing date of the instant application’s U.S.
priority application, 62/198,166) because the contents of the claimed invention are
substantially the same as the features disclosed in the U.S. priority application. Applicant notes
that [Prior Art] was filed on December 9, 2015, which is later than the effective filing date of the
instant application.
Thus, with respect to the instant application, [Prior Art] only qualifies as prior art against
the presently claimed invention for subject matter included in [Prior Art]’s provisional
application 62/161,761 (hereinafter “[Prior Art]_Provisional”), which was filed on May 14, 2015.