Tiny code refactor

src/appier/model.py

@@ -1174,7 +1174,7 @@ def fill(cls, model = None, safe = False):
             if private and safe: continue
             if increment: continue
             if "initial" in _definition:
-                initial = _definition.get("initial")
+                initial = _definition["initial"]
                 model[name] = initial
             else:
                 _type = _definition.get("type")