diff --git a/src/festim/helpers.py b/src/festim/helpers.py
index 761a914d2..9618fddf4 100644
--- a/src/festim/helpers.py
+++ b/src/festim/helpers.py
@@ -50,6 +50,7 @@ def as_mapped_function(
         The mapped function
     """
 
+    # Extract the input variable names in the callable function `value`
     arguments = value.__code__.co_varnames
 
     kwargs = {}
@@ -135,7 +136,6 @@ class Value:
     fenics_object: fem.Function | fem.Constant | ufl.core.expr.Expr
 
     def __init__(self, input_value):
-        (self,)
         self.input_value = input_value
 
         self.ufl_expression = None