diff --git a/consumer/api/cpp/include/consumer/data_broker.h b/consumer/api/cpp/include/consumer/data_broker.h
index 664554b0e1e6788619acc808c0a744139b1ddb63..e76881e85a2419b48257f042006cf7dfb4afc850 100644
--- a/consumer/api/cpp/include/consumer/data_broker.h
+++ b/consumer/api/cpp/include/consumer/data_broker.h
@@ -74,7 +74,7 @@ class DataBroker {
      */
     virtual NetworkConnectionType CurrentConnectionType() const = 0;
 
-    //! Set list of substreams
+    //! Get list of substreams, set from to "" to get all substreams
     virtual StreamInfos GetSubstreamList(std::string from, Error* err) = 0;
 
     //! Get current number of datasets
diff --git a/consumer/api/python/asapo_consumer.pyx.in b/consumer/api/python/asapo_consumer.pyx.in
index 17981635725b324802911d45b0af035e577f8da5..0022eef0a3f6e76122e0640efdd3bc23aea52f8c 100644
--- a/consumer/api/python/asapo_consumer.pyx.in
+++ b/consumer/api/python/asapo_consumer.pyx.in
@@ -203,7 +203,7 @@ cdef class PyDataBroker:
         if err:
             throw_exception(err)
         return _str(group_id)
-    def get_substream_list(self,from_substream):
+    def get_substream_list(self, from_substream = ""):
         cdef Error err
         cdef vector[StreamInfo] substreams
         cdef string b_from_substream = _bytes(from_substream)