[Repo Assist] fix(utils): capture loop variable in create_polynomial_function via default arg (#1763)

fix: capture loop variable in create_polynomial_function via default arg

The inner function poly_term captured the loop variable 'degree' by
reference, so every function in the returned list evaluated to
x^max_degree regardless of its index. Fix by binding each value via
a default argument (_degree=degree).

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dowhy/utils/regression.py

@@ -42,8 +42,8 @@ def create_polynomial_function(max_degree):
     polynomial_function = []
     for degree in range(max_degree + 1):
 
-        def poly_term(x):
-            return x[:, [0]] ** degree
+        def poly_term(x, _degree=degree):
+            return x[:, [0]] ** _degree
 
         polynomial_function.append(poly_term)
     return polynomial_function