Function plot_dynamic_spectrum_freq 

pub fn plot_dynamic_spectrum_freq(
    output_path: &str,
    spectrum_array: &Array2<Complex<f32>>,
    header: &CorHeader,
    obs_time: &DateTime<Utc>,
    _length: i32,
    _effective_integration_time: f32,
) -> Result<(), Box<dyn Error>>