This function applies a bandpass filter to a signal.
It first normalizes the high and low frequencies based on the Nyquist frequency,
then creates a Butterworth filter using the `signal::butter` function,
and finally applies the filter to the signal using `signal::filtfilt`.

`bandpass(x, high, low, sRate, order = 5)`

## Arguments

- x
A numeric vector representing the signal to be filtered.

- high
The high cutoff frequency for the bandpass filter.

- low
The low cutoff frequency for the bandpass filter.

- sRate
The sampling rate of the signal.

- order
The order of the Butterworth filter, defaulting to 5.

## Value

A numeric vector representing the filtered signal.

## References

If applicable, add references here.

## Examples

```
sample_signal <- sin(seq(0, 10, length.out = 1000))
filtered_signal <- bandpass(sample_signal, high = 0.3, low = 0.1, sRate = 100)
```