nameshift <- c(SL = 'Sepal.Length')
head(dplyr::rename(iris[,1:2], ! ! ! nameshift), 3)
head(dplyr::rename(iris[,1:2],!! ! nameshift), 3)
head(dplyr::rename(iris[,1:2], !!!nameshift), 3)
my_summarise <- function(df, group_var) {
  df %>%
    group_by( ! ! group_var) %>%
    summarise(a = mean(a))
}