library(rvest)
> library
function (package, help, pos = 2, lib.loc = NULL, character.only = FALSE,
    logical.return = FALSE, warn.conflicts, quietly = FALSE,
    verbose = getOption("verbose"), mask.ok, exclude, include.only,
    attach.required = missing(include.only))
{
    conf.ctrl <- getOption("conflicts.policy")
    if (is.character(conf.ctrl))
        conf.ctrl <- switch(conf.ctrl, strict = list(error = TRUE,
            warn = FALSE), depends.ok = list(error = TRUE, generics.ok = TRUE,
            can.mask = c("base", "methods", "utils",
                "grDevices", "graphics", "stats"),
            depends.ok = TRUE), warning(gettextf("unknown conflict policy: %s",
            sQuote(conf.ctrl)), call. = FALSE, domain = NA))
    if (!is.list(conf.ctrl))
        conf.ctrl <- NULL
    stopOnConflict <- isTRUE(conf.ctrl$error)
    if (missing(warn.conflicts))
        warn.conflicts <- if (isFALSE(conf.ctrl$warn))
            FALSE
        else TRUE