Unsupported native gates

src/qibo/transpiler/unroller.py

@@ -4,7 +4,7 @@
 
 from qibo import gates
 from qibo.backends import _check_backend
-from qibo.config import raise_error
+from qibo.config import log, raise_error
 from qibo.models import Circuit
 from qibo.transpiler._exceptions import DecompositionError
 from qibo.transpiler.decompositions import (
@@ -22,7 +22,10 @@ class FlagMeta(EnumMeta):
 
     def __getitem__(cls, keys):
         if isinstance(keys, str):
-            return super().__getitem__(keys)
+            try:
+                return super().__getitem__(keys)
+            except KeyError:
+                return super().__getitem__("NONE")
         return reduce(or_, [cls[key] for key in keys])  # pylint: disable=E1136
 
 
@@ -44,6 +47,7 @@ class NativeGates(Flag, metaclass=FlagMeta):
         - :class:`qibo.gates.gates.CNOT`
     """
 
+    NONE = 0
     I = auto()
     Z = auto()
     RZ = auto()

tests/test_transpiler_unroller.py

@@ -27,8 +27,8 @@ def test_native_gate_str_list():
     for gate in testlist:
         assert NativeGates[gate] in natives
 
-    with pytest.raises(KeyError):
-        NativeGates[["qi", "bo"]]  # Invalid gate names
+    natives = NativeGates[["qi", "bo"]]  # Invalid gate names
+    assert natives == NativeGates(0)
 
 
 def test_translate_gate_error_1q():