overwrite build model by some method which applies the downcast directly

Former-commit-id: f796834082

stormpy/core/__init__.py

@@ -1 +1,20 @@
 from stormpy.core._core import *
+        
+def _build_model(program, formulae):
+    intermediate = _core.build_model(program, formulae)
+    if intermediate.parametric:
+        if intermediate.model_type == ModelType.DTMC:
+            return intermediate.as_pdtmc()
+        elif intermediate.model_type == ModelType.MDP:
+            return intermediate.as_pmdp()
+        else:
+            raise RuntimeError("Not supported parametric model constructed")
+    else:
+        if intermediate.model_type == ModelType.DTMC:
+            return intermediate.as_pdtmc()
+        elif intermediate.model_type == ModelType.MDP:
+            return intermediate.as_pmdp()
+        else:
+            raise RuntimeError("Not supported non-parametric model constructed")
+
+build_model = _build_model