GaudiConfig2: allow implicit conversion from tuple for ListHelper

To support `Gaudi::Property<DataOjbIDColl>` we need to allow implicit
conversion from `tuple`.

GaudiConfiguration/python/GaudiConfig2/semantics.py

@@ -360,9 +360,11 @@ class SequenceSemantics(PropertySemantics):
         self.value_semantics.name = "{} element".format(self._name)
 
     def store(self, value):
-        if not isinstance(value, (list, _ListHelper)):
+        if not isinstance(value, (list, _ListHelper, tuple)):
             raise TypeError(
-                "list expected, got {!r} in assignment to {}".format(value, self.name)
+                "list or tuple expected, got {!r} in assignment to {}".format(
+                    value, self.name
+                )
             )
         new_value = _ListHelper(self.value_semantics)
         new_value.extend(value)

GaudiConfiguration/tests/python/test_sequence_semantics.py

@@ -84,6 +84,15 @@ def test_opt_value():
     assert s.opt_value(d) == ["a", "b", "c"]
 
 
+def test_implicit_conversion():
+    s = S.getSemanticsFor("std::vector<std::string, alloc<string> >")
+
+    # For backwards-compatibility (i.e. for Property<DataObjIDColl>)
+    # we support assignment from tuple:
+    d = s.store(("a", "b", "c"))
+    assert d == list("abc")
+
+
 def test_assignment_bad():
     s = S.getSemanticsFor("std::vector<std::string, alloc<string> >")
     with pytest.raises(TypeError):