DeprecationWarning: `np.float` is a deprecated alias for the builtin `float`

DeprecationWarning: \`np.float\` is a deprecated alias for the builtin \`float\`. To silence this warning, use \`float\` by itself. Doing this will not modify any behavior and is safe. If you specifically wanted the numpy scalar type, use \`np.float64\` here. Deprecated in NumPy 1.20; for more details and guidance: [https://numpy.org/devdocs/release/1.20.0](https://numpy.org/devdocs/release/1.20.0)ㅡ notes.html#deprecations

• Solution

 spec = librosa.stft(mixed,window='hann',n_fft=n_fft,hop_length=n_shift, win_length=None,center=False)

=>

spec = librosa.stft(mixed,window='hann',n_fft=n_fft,hop_length=n_shift, win_length=None,center=False,dtype=np.cdouble)

• 원인을 추측해보자면 기본값이 complex float 64인데, 최신 버전에서는입력과 같은 타입을 사용한다고 한다.
• 이거 때문에 librosa 내부에서 캐스팅을 수행할 때 최신 버전의 numpy와 호환이 안되서
  문제가 발생하것 같다. 
• https://librosa.org/doc/0.8.0/generated/librosa.stft.html
• https://librosa.org/doc/0.7.2/generated/librosa.core.stft.html