fix typespec #306

Job	Run time
static analysis (Elixir 1.15.x \| Erlang/OTP 26.x)	56s
mix test windows (Elixir 1.13.x \| Erlang/OTP 22.x)	2m 2s
mix test windows (Elixir 1.13.x \| Erlang/OTP 23.x)	2m 55s
mix test windows (Elixir 1.13.x \| Erlang/OTP 24.x)	2m 41s
mix test windows (Elixir 1.13.x \| Erlang/OTP 25.x)	2m 22s
mix test windows (Elixir 1.14.x \| Erlang/OTP 23.x)	3m 6s
mix test windows (Elixir 1.14.x \| Erlang/OTP 24.x)	2m 38s
mix test windows (Elixir 1.14.x \| Erlang/OTP 25.x)	2m 17s
mix test windows (Elixir 1.14.x \| Erlang/OTP 26.x)	2m 45s
mix test windows (Elixir 1.15.x \| Erlang/OTP 24.x)	1m 59s
mix test windows (Elixir 1.15.x \| Erlang/OTP 25.x)	2m 38s
mix test windows (Elixir 1.15.x \| Erlang/OTP 26.x)	2m 36s
mix test (Elixir 1.13.x \| Erlang/OTP 22.x)	1m 20s
mix test (Elixir 1.13.x \| Erlang/OTP 23.x)	1m 30s
mix test (Elixir 1.13.x \| Erlang/OTP 24.x)	1m 17s
mix test (Elixir 1.13.x \| Erlang/OTP 25.x)	1m 11s
mix test (Elixir 1.14.x \| Erlang/OTP 23.x)	1m 41s
mix test (Elixir 1.14.x \| Erlang/OTP 24.x)	1m 15s
mix test (Elixir 1.14.x \| Erlang/OTP 25.x)	1m 14s
mix test (Elixir 1.14.x \| Erlang/OTP 26.x)	1m 26s
mix test (Elixir 1.15.x \| Erlang/OTP 24.x)	1m 3s
mix test (Elixir 1.15.x \| Erlang/OTP 25.x)	1m 7s
mix test (Elixir 1.15.x \| Erlang/OTP 26.x)	1m 7s
	43m 6s

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