diff --git a/Model.py b/Model.py
index 0e31841..bc774f3 100644
--- a/Model.py
+++ b/Model.py
@@ -348,6 +348,9 @@ class Model:
             FCa_0,  # FCa
         ]
 
+    def calculated_current():
+        return None
+
     def solve(self, initial_values, tspan, dt, times):
         times = np.arange(*tspan, dt)
 
diff --git a/__pycache__/Model.cpython-311.pyc b/__pycache__/Model.cpython-311.pyc
index ef00b29..421bef4 100644
Binary files a/__pycache__/Model.cpython-311.pyc and b/__pycache__/Model.cpython-311.pyc differ
diff --git a/fitter.py b/fitter.py
index 9e8ab2d..e527ec5 100644
--- a/fitter.py
+++ b/fitter.py
@@ -65,7 +65,7 @@ class Fitter:
             times=self.time_points,
             tspan=self.tspan,
             dt=self.dt,
-            initial_values=self.initial_values,
+            initial_values=self.initial_values
         )
 
         _calc_curr = model.calculated_current()