Function visualize_learning_curve 

pub fn visualize_learning_curve(
    train_sizes: Vec<usize>,
    train_scores: Vec<Vec<f64>>,
    val_scores: Vec<Vec<f64>>,
    score_name: impl Into<String>,
) -> Result<Box<dyn MetricVisualizer>, Box<dyn Error>>

Create a learning curve visualization

Arguments

• train_sizes - Training set sizes
• train_scores - Training scores (multiple runs for each size)
• val_scores - Validation scores (multiple runs for each size)
• score_name - Name of the score (e.g., “Accuracy”)

Returns

• Box<dyn crate::visualization::MetricVisualizer> - A visualizer for the learning curve
• Result<Box<dyn crate::visualization::MetricVisualizer>, Box<dyn Error>> - A visualizer for the learning curve, or an error