Add degrees of freedom property

Author: ZeroCool2u

csaps/_sspumv.py

@@ -53,6 +53,10 @@ def pieces(self) -> int:
     def gcv(self) -> float:
         return self.gcv
 
+    @property
+    def degrees_of_freedom(self) -> float:
+        return self.degrees_of_freedom
+
     @property
     def ndim(self) -> int:
         """Returns the number of spline dimensions