correct specification to allow undefined nonces
diff --git a/src/rexi_server.erl b/src/rexi_server.erl
index 980f7d6..a261828 100644
--- a/src/rexi_server.erl
+++ b/src/rexi_server.erl
@@ -121,7 +121,8 @@
init_p(From, MFA, undefined).
%% @doc initializes a process started by rexi_server.
--spec init_p({pid(), reference()}, {atom(), atom(), list()}, string()) -> any().
+-spec init_p({pid(), reference()}, {atom(), atom(), list()},
+ string() | undefined) -> any().
init_p(From, {M,F,A}, Nonce) ->
put(rexi_from, From),
put(initial_call, {M,F,length(A)}),