XEts.KV.member-question-mark

You're seeing just the function member-question-mark, go back to XEts.KV module for more information.
Link to this function

member?(map, key)

Specs

member?(t(), any()) :: boolean()

Test if key is a member.

iex> :foo |> XEts.KV.new([]) |> XEts.KV.put(:x, nil) |> XEts.KV.member?(:x)
true

iex> :bar |> XEts.KV.new([]) |> XEts.KV.member?(:x)
false