date_list_1 <- c("2021-09-12", "2016-xx-02",
"09/08/2012")
date_checker(date_list_1)
#> FALSE (Entries 2 and 3
#are incorrect date inputs)
date_list_2 <- c("2021-09-12", "1998-03-09")
date_checker(date_list_2)
#> TRUE
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