def save_each_channel(image_with_four_channels):
   #Assuming that the images is having shape (C, H, W)

   channel_one = image_with_four_channels[0]
   channel_two = image_with_four_channels[1]
   channel_three = image_with_four_channels[2]
   channel_four = image_with_four_channels[3]

   np.savez("separate_channels.npz", channel_one_key = channel_one, channel_two_key = channel_two, channel_three_key = channel_three, channel_four_key = channel_four)

def load_each_channel():
    separate_channels = np.load("separate_channels.npz")
    channel_one = separate_channels["channel_one_key"]
    channel_two = separate_channels["channel_two_key"]
    channel_three = separate_channels["channel_three_key"]
    channel_four = separate_channels["channel_four_key"]