Avoid [] as default parameter

src/AsapoWorker/asapo_sender.py

@@ -153,7 +153,7 @@ class AsapoSender:
     def __attrs_post_init__(self):
         log.info("Receiver created with ingest_mode=%s", self.ingest_mode)
 
-    def send_data(self, data, metadata, acknowledge=[], ack_dependencies=None):
+    def send_data(self, data, metadata, acknowledge=None, ack_dependencies=None):
         log.info(
             "Sending data with id=%s name=%s",
             metadata["_id"], metadata["name"])
@@ -162,6 +162,8 @@ class AsapoSender:
 
             if ack_dependencies is None:
                 ack_dependencies = set([metadata["_id"]])
+            if acknowledge is None:
+                acknowledge = []
             for out_id in acknowledge:
                 if out_id not in self._ids_to_acknowledge:
                     self._ids_to_acknowledge[out_id] = ack_dependencies

src/AsapoWorker/worker.py

@@ -80,7 +80,7 @@ class Worker:
         """
         pass
 
-    def send(self, data, metadata, acknowledge=[], ack_dependencies=None):
+    def send(self, data, metadata, acknowledge=None, ack_dependencies=None):
         if self.sender:
             self.sender.send_data(
                 data, metadata, acknowledge=acknowledge, ack_dependencies=to_set(ack_dependencies))
@@ -88,7 +88,7 @@ class Worker:
             raise ConfigurationError(
                 "Worker wants to send data, but no sender configured!")
 
-    def send_acknowledgement(self, acknowledge=[]):
+    def send_acknowledgement(self, acknowledge=None):
         self._acknowledge(self.sender.data_source, acknowledge)