import numpy as np

train_dataset = np.load('msd-10-genre-train.npz')
valid_dataset = np.load('msd-10-genre-valid.npz')

assert np.all( train_dataset['label_map'] == valid_dataset['label_map'] )

np.savez(
    'msd-10-genre-train_valid.npz',
    inputs = np.concatenate((train_dataset['inputs'], valid_dataset['inputs'])),
    targets = np.concatenate((train_dataset['targets'], valid_dataset['targets'])),
    label_map = train_dataset['label_map']
)