A junior data scientist is building a model to predict a customer's likelihood of making a purchase. The model uses the customer's age and income as inputs. The model's behavior is defined by a set of internal values, represented by θ. The data scientist documents the model's function as: likelihood = predict(age, income, θ). Based on the standard convention for writing parameterized functions, analyze this notation. Identify any potential ambiguity or deviation from the standard, and explain how you would rewrite it for better clarity.