Alchemy.Voice.wait_for_end

You're seeing just the function wait_for_end, go back to Alchemy.Voice module for more information.
Link to this function

wait_for_end(guild, timeout \\ :infinity)

Specs

wait_for_end(snowflake(), integer() | :infinity) :: :ok | {:error, String.t()}

Blocks the current process until audio has stopped playing in a guild.

This is a combination of listen_for_end/1 and a receive block, however this will return an error if the provided timeout is exceeded. This is useful for implementing automatic track listing, e.g.

def playlist(guild, tracks) do
  Enum.map(tracks, fn track ->
    Voice.play_file(guild, track)
    Voice.wait_for_end(guild)
  end)
end