get_substream_list - return all substreams by default in python

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

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)