You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: get_year.rs
    path of file: ./repos/nushell/crates/nu-cmd-dataframe/src/dataframe/series/date
    
    the code of the file until where you have to start completion: use super::super::super::values::{Column, NuDataFrame};

use nu_protocol::{
    ast::Call,
    engine::{Command, EngineState, Stack},
    Category, Example, PipelineData, ShellError, Signature, Span, Type, Value,
};
use polars::prelude::{DatetimeMethods, IntoSeries};

#[derive(Clone)]
pub struct GetYear;

    
    fn examples(&self) -> Vec<Example> {
        vec![Example {
            description: "Returns year from a date",
            example: r#"let dt = ('2020-08-04T16:39:18+00:00' | into datetime --timezone 'UTC');
    let df = ([$dt $dt] | dfr into-df);
    $df | dfr get-year"#,
            result: Some(
                NuDataFrame::try_from_columns(
                    vec![Column::new(
                        "0".to_string(),
                        vec![Value::test_int(2020), Value::test_int(2020)],
                    )],
                    None,
                )
                .expect("simple df for test should not fail")
                .into_value(Span::test_data()),
            ),
        }]
    }