Docstring fix in gammapy/cube/models.py
@@ -241,7 +241,7 @@ class CompoundSkyModel(object):
class SumSkyModel(object):
- """Sum of a list of `SkyModel`s.
+ """Sum of independent `SkyModel` components.
Not sure if we want this class, or only a + operator on SkyModel.
If we keep it, then probably SkyModel should become an ABC
