Single energy runs

GiBUU provides the possibility to run at single energy, which provides different output files. This should be covered with KM3BUU.

km3buu/output.py

@@ -258,9 +258,9 @@ class GiBUUOutput:
 
     @property
     def mean_xsec(self):
-        if self.flux_data is None
+        if self.flux_data is None:
             return lambda energy: self.xsection["sum"]
-        else
+        else:
             root_tupledata = self.arrays
             energies = np.array(root_tupledata.lepIn_E)
             weights = self._event_xsec(root_tupledata)
@@ -269,8 +269,8 @@ class GiBUUOutput:
             xsec, energy_bins = np.histogram(energies,
                                              weights=weights,
                                              bins=np.logspace(
-                                                 np.log10(Emin), np.log10(Emax),
-                                                 15))
+                                                 np.log10(Emin),
+                                                 np.log10(Emax), 15))
             deltaE = np.mean(self.flux_data["energy"][1:] -
                              self.flux_data["energy"][:-1])
             bin_events = np.array([