update Docstring PropagatorOperator

1a41b00b · Pumpe, Daniel (dpumpe) · f6fb0545 · 1a41b00b
Commit 1a41b00b authored May 09, 2017 by Pumpe, Daniel (dpumpe)
--- a/nifty/operators/propagator_operator/propagator_operator.py
+++ b/nifty/operators/propagator_operator/propagator_operator.py
@@ -50,6 +50,9 @@ class PropagatorOperator(InvertibleOperatorMixin, EndomorphicOperator):

    Raises
    ------
+    ValueError
+        is raised if
+            * neither N nor M is given

    Notes
    -----