diff --git a/nifty5/operators/simple_linear_operators.py b/nifty5/operators/simple_linear_operators.py
index ba7c3eecc8e52cd050827492089084e94adac4fd..f8c7c75d99ab69eb312c3bb22958301c66a8fb93 100644
--- a/nifty5/operators/simple_linear_operators.py
+++ b/nifty5/operators/simple_linear_operators.py
@@ -187,9 +187,7 @@ class _SlowFieldAdapter(LinearOperator):
         self._check_input(x, mode)
         if isinstance(x, MultiField):
             return x[self._name]
-        else:
-            return MultiField.from_dict({self._name: x},
-                                        domain=self._tgt(mode))
+        return MultiField.from_dict({self._name: x}, domain=self._tgt(mode))
 
     def __repr__(self):
         return '_SlowFieldAdapter'
diff --git a/test/test_operators/test_adjoint.py b/test/test_operators/test_adjoint.py
index f89fdedcda14f9729fb8c7341fac173764a5e6bf..9e37ee82a8c76fff443c142c2abc45df763cf1fb 100644
--- a/test/test_operators/test_adjoint.py
+++ b/test/test_operators/test_adjoint.py
@@ -319,3 +319,10 @@ def testPartialExtractor(seed):
     tgt = ift.MultiDomain.make(tgt)
     op = ift.PartialExtractor(dom, tgt)
     ift.extra.consistency_check(op)
+
+
+@pmp('seed', [12, 3])
+def testSlowFieldAdapter(seed):
+    dom = {'a': ift.RGSpace(1), 'b': ift.RGSpace(2)}
+    op = ift.operators.simple_linear_operators._SlowFieldAdapter(dom, 'a')
+    ift.extra.consistency_check(op)