librosa.load时发生FileNotFoundError: [WinError 2] 系统找不到指定的档案。

import librosa
import matplotlib.pyplot as plt
import numpy as np
import librosa.display
import IPython.display as ipd
%matplotlib inline

filepath = './audio_train/happy/'
filename = filepath + '00334.wav'

ipd.Audio(filename) #load a local happy.wav

y, sr = librosa.load(filename)

FileNotFoundError: [WinError 2] 系统找不到指定的档案。