Query @select nested in a function


I have an issue using Query @select using a function call parameter to select columns:

using Query, VegaDatasets

iris = dataset("iris")

iris |> @select(startswith("petal"))
# This works of course

function get_data(df, tag)
    df |>
        @select(startswith(tag)) |>

get_data(iris, "petal")
# All columns are removed

Is this an incorrect way of using the Query syntax?
What is the recommended way for making such helper functions?