failed to use frequency_domain.frequency_domain() function

Hi, I've tried to use the frequency_domain.frequency_domain() function as follow:
`test = np.array([...])
res = frequency_domain.frequency_domain(signal=test)`
But it raised this error: AttributeError: module 'biosppy.inter_plotting.ecg' has no attribute 'ecg'. Could you please help me? :)