Alchemy.Voice.play_iodata

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

play_iodata(guild, data, options \\ [])

Specs

play_iodata(snowflake(), iodata() | Enumerable.t(), audio_options()) ::
  :ok | {:error, String.t()}

Starts playing audio from an iodata, or a stream of iodata.

Similar to play_url/2 except it doesn't create a stream from youtube-dl for you.