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: fft.rs
    path of file: ./repos/tract/core/src/ops
    
    the code of the file until where you have to start completion: use crate::internal::*;
use num_complex::Complex;
use rustfft::num_traits::{Float, FromPrimitive};
use rustfft::{FftDirection, FftNum};
use tract_data::itertools::Itertools;
use tract_ndarray::Axi
    
    fn eval(&self, inputs: TVec<TValue>) -> TractResult<TVec<TValue>> {
        let mut tensor = args_1!(inputs).into_tensor();
        match tensor.datum_type() {
            DatumType::F16 => {
                let mut temp = tensor.cast_to::<f32>()?.into_owned();
                self.eval_t::<f32>(&mut temp)?;
                tensor = temp.cast_to::<f16>()?.into_owned();
            }
            DatumType::F32 => self.eval_t::<f32>(&mut tensor)?,
            DatumType::F64 => self.eval_t::<f64>(&mut tensor)?,
            _ => bail!("FFT not implemented for type {:?}", tensor.datum_type()),
        }
        Ok(tvec!(tensor.into_tvalue()))
    }