apply Patrick suggestions

Phys/DecayTreeFitter/python/DecayTreeFitter/DecayTreeFitter.py

@@ -102,7 +102,7 @@ class DecayTreeFitter:
 
         # Config algorithm
         if input_pvs:
-            self.HasPVConstrain = True
+            self.HasPVConstraint = True
             gaudi_algorithm = DecayTreeFitterAlg_v1Particle_AllPVs if fit_all_pvs else DecayTreeFitterAlg_v1Particle_BestPV
             # If is v2 vertex
             if 'LHCb::Event::PV::PrimaryVertexContainer' in input_pvs.type:
@@ -121,7 +121,7 @@ class DecayTreeFitter:
                 MassConstraints=mass_constraints,
                 OutputLevel=output_level)
         else:
-            self.HasPVConstrain = False
+            self.HasPVConstraint = False
             self.Algorithm = DecayTreeFitterAlg_v1Particle(
                 name=name,
                 Input=DTF_input,