'Constructs a postprocessor.
Args:
pca_params_npz_path: Path to a NumPy-format .npz file that
contains the PCA parameters used in postprocessing.'

def __init__(self, pca_params_npz_path):

    params = np.load(pca_params_npz_path)
    self._pca_matrix = params[vggish_params.PCA_EIGEN_VECTORS_NAME]
    self._pca_means = params[vggish_params.PCA_MEANS_NAME].reshape((-1), 1)
    assert (self._pca_matrix.shape == (vggish_params.EMBEDDING_SIZE, vggish_params.EMBEDDING_SIZE)), ('Bad    PCA    matrix    shape:    %r' % (self._pca_matrix.shape,))
    assert (self._pca_means.shape == (vggish_params.EMBEDDING_SIZE, 1)), ('Bad    PCA    means    shape:    %r' % (self._pca_means.shape,))
