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: var_to.rs
    path of file: ./repos/dfdx/dfdx-core/src/tensor_ops
    
    the code of the file until where you have to start completion: use super::*;
use crate::{shapes::*, tensor::*};

/// Reduction alogn multiple axes using variance
pub trait VarTo: Sized + HasShape {
    /// Result [Tensor] has smaller number of dimensions.
    ///
    /// **Pytorch equivalent**: `t.var(Axes, unbiased=False)`
    ///
    /// Examples:
    /// ```rust
    /// # use 
    
    fn test_var_axis_0_2d() {
        let dev: TestDevice = Default::default();
        let t = dev
            .tensor([[1.0, 2.0, 3.0, 4.0], [0.0, 2.0, 5.0, 10.0]])
            .to_dtype::<TestDtype>();
        let r = t.leaky_trace().var::<Rank1<4>, _>();
        assert_close_to_literal!(r, [0.25, 0.0, 1.0, 9.0]);
        let g = r.mean().backward();
        assert_close_to_literal!(
            g.get(&t),
            [[0.125, 0.0, -0.25, -0.75], [-0.125, 0.0, 0.25, 0.75]]
        );
    }