Fix list -> binary arg

src/hz.erl

@@ -796,7 +796,7 @@ contract_code(ID) ->
 
 contract_source(ID) ->
     case request(["/v3/contracts/", ID, "/source"]) of
-        {ok, #{"source" := Blobby}} -> extract(Blobby);
+        {ok, #{"source" := Blobby}} -> extract(list_to_binary(Blobby));
         {ok, #{"reason" := Reason}} -> {error, Reason};
         Error                       -> Error
     end.