fix flake8; import

emg3d/inversion/__init__.py

@@ -13,5 +13,3 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 # License for the specific language governing permissions and limitations under
 # the License.
-
-from emg3d.inversion import pygimli

emg3d/inversion/pygimli.py

@@ -32,8 +32,7 @@ def __dir__():
     return __all__
 
 
-@utils._requires('pygimli')
-class Kernel(pygimli.Modelling):
+class Kernel(pygimli.Modelling if pygimli else object):
     """Create a forward operator of emg3d to use within a pyGIMLi inversion.
 
 
@@ -57,6 +56,7 @@ class Kernel(pygimli.Modelling):
 
     """
 
+    @utils._requires('pygimli')
     def __init__(self, simulation, markers=None, pgthreads=2):
         """Initialize a pyGIMLi(emg3d)-wrapper."""
         super().__init__()
@@ -90,7 +90,7 @@ def __init__(self, simulation, markers=None, pgthreads=2):
             self.markers = markers
         else:
             self.markes = np.zeros(simulation.model.size, dtype=int)
-        # Store original properties; required if a region is set to ``background``.
+        # Store original props; required if a region is set to ``background``.
         self._model = simulation.model.property_x.copy()
         # Store volumes; required if a region is set to ``single``.
         self._volumes = simulation.model.grid.cell_volumes.reshape(
@@ -217,7 +217,7 @@ def model2emg3d(self, model):
 
         return out
 
-    class Jacobian(pygimli.Matrix):
+    class Jacobian(pygimli.Matrix if pygimli else object):
         """Return Jacobian operator for pyGIMLi(emg3d)."""
 
         def __init__(self, simulation,
@@ -253,9 +253,10 @@ def save(self, *args):
 
 
 @utils._requires('pygimli')
-class Inversion(pygimli.Inversion):
+class Inversion(pygimli.Inversion if pygimli else object):
     """Thin wrapper, adding verbosity and taking care of data format."""
 
+    @utils._requires('pygimli')
     def __init__(self, fop=None, inv=None, **kwargs):
         """Initialize an Inversion instance."""
         super().__init__(fop=fop, inv=inv, **kwargs)