d <- tibble::tibble(a_DTS = c("2018-3-25", "2018-3-25"),
b_nums = c(2, 4),
c_DTS = c("03-01-2018", "03-07-2018"),
d_chars = c("a", "b"),
e_date = lubridate::mdy(c("3-25-2018", "3-25-2018")))
convert_date_cols(d)
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