def _gather_channels(x, indexes, **kwargs):
    """Slice tensor along channels axis by given indexes"""
    backend = kwargs['backend']
    if backend.image_data_format() == 'channels_last':
        x = backend.permute_dimensions(x, (3, 0, 1, 2))
        x = backend.gather(x, indexes)
        x = backend.permute_dimensions(x, (1, 2, 3, 0))
    else:
        x = backend.permute_dimensions(x, (1, 0, 2, 3))
        x = backend.gather(x, indexes)
        x = backend.permute_dimensions(x, (1, 0, 2, 3))
    return x
Slice tensor along channels axis by given indexes
segmentation_models/base/functional.py