This example code should explains what I mean well: ```r library(blastula) files <- c(tempfile(fileext = ".txt"), tempfile(fileext = ".txt")) writeLines("file1", files[1]) writeLines("file2", files[2]) email <- compose_email("test") out1 <- add_attachment(email, files)$attachments out2 <- local({ email <- add_attachment(email, files[1]) email <- add_attachment(email, files[2]) email$attachments }) ``` `out1` and `out2` should generate the same result. However, at present, `smtp_send()` will fail when `out1` is used for the `email` argument.