Function last_value 

pub fn last_value(values: &[Option<f64>]) -> Option<f64>

Helper function to extract the last non-None value from a vector.

Useful for converting historical indicator values to latest value only.

Example

use finance_query::indicators::last_value;

let values = vec![None, None, Some(10.0), Some(20.0)];
assert_eq!(last_value(&values), Some(20.0));