(self, paths)
return NotImplementedError()
generate mean and vars of features,
            paths: list or tuple
generate mean and vars of features,
            paths: list or tuple
generate mean and vars of features paths : list or tuple
def generate_cmvn(self, paths):
    '''
        generate mean and vars of features,
            paths: list or tuple
        '''
    return NotImplementedError()
def generate_cmvn ( self , paths ) : return NotImplementedError ( )