Make zfit requirement flexible

pyproject.toml

@@ -18,7 +18,7 @@ classifiers = [
 dependencies = [
     "numpy>=1.16",
     "pandas",
-    "zfit==0.21.0",
+    "zfit>0.21.0",
     "tensorflow",
     "tensorflow-probability",
     "keras",

src/zfitwrapper/Fitter.py

@@ -31,7 +31,8 @@ class Fitter(BaseFitter):
 
     @property
     def lossfunction(self) -> Type[zfit.core.loss.BaseLoss]:
-        if self.ext_loss:
+        assert self.model.model is not None
+        if self.model.model.is_extended:
             lossfunction = zfit.loss.ExtendedUnbinnedNLL
         else:
             lossfunction = zfit.loss.UnbinnedNLL
@@ -42,14 +43,8 @@ class Fitter(BaseFitter):
     def eval_model(
         self,
     ) -> Union[zfit.core.basepdf.BasePDF, zfit.core.interfaces.ZfitPDF]:
-        if self.ext_loss:
-            eval_model = self.model.ext_model
-            assert isinstance(eval_model, zfit.core.interfaces.ZfitPDF)
-        else:
-            eval_model = self.model.model
-            assert eval_model is not None
-
-        return eval_model
+        assert self.model.model is not None
+        return self.model.model
 
     @property
     def gof(self) -> float:
@@ -102,7 +97,8 @@ class HistFitter(BaseFitter):
 
     @property
     def lossfunction(self) -> Type[zfit.core.loss.BaseLoss]:
-        if self.ext_loss:
+        assert self.model.model is not None
+        if self.model.model.is_extended:
             lossfunction = zfit.loss.ExtendedBinnedNLL
         else:
             lossfunction = zfit.loss.BinnedNLL
@@ -113,14 +109,8 @@ class HistFitter(BaseFitter):
     def eval_model(
         self,
     ) -> Union[zfit.core.basepdf.BasePDF, zfit.core.interfaces.ZfitPDF]:
-        if self.ext_loss:
-            assert isinstance(self.model.ext_model, zfit.core.interfaces.ZfitPDF)
-            eval_model = zfit.pdf.BinnedFromUnbinnedPDF(self.model.ext_model, self.obs)
-        else:
-            assert self.model.model is not None
-            eval_model = zfit.pdf.BinnedFromUnbinnedPDF(self.model.model, self.obs)
-
-        return eval_model
+        assert self.model.model is not None
+        return zfit.pdf.BinnedFromUnbinnedPDF(self.model.model, self.obs)
 
     @property
     def gof(self) -> float: