escript module not available from elixir

erl

Erlang/OTP 18 [erts-7.2] [source] [64-bit] [async-threads:10] [kernel-poll:false]

Eshell V7.2  (abort with ^G)
1> escript:extract("demo", []).
{ok,[{shebang,default},
     {comment,[]},
     {emu_args,"-escript main demo_escript"},
     {archive,<<80,75,3,4,20,0,0,0,8,0,231,157,92,72,33,101,
                158,13,85,12,0,...>>}]}

iex

Erlang/OTP 18 [erts-7.2] [source] [64-bit] [async-threads:10] [kernel-poll:false]

Interactive Elixir (1.2.0) - press Ctrl+C to exit (type h() ENTER for help)

iex(1)> :escript.extract("demo", [])
** (FunctionClauseError) no function clause matching in :escript.extract/2
    (stdlib) escript.erl:163: :escript.extract("demo", [])

Convert "demo" to 'demo'
Erlang expects a char list for file.
Escript.erl

:escript.extract('demo', [])