(outer_filters, bottleneck_filters)
return compose(
        bottleneck_block(outer_filters, bottleneck_filters),
        DarknetConv2D_BN_Leaky(bottleneck_filters, (1, 1)),
        DarknetConv2D_BN_Leaky(outer_filters, (3, 3)))
Bottleneck block of 3x3, 1x1, 3x3, 1x1, 3x3 convolutions.
Bottleneck block of 3x3, 1x1, 3x3, 1x1, 3x3 convolutions.
Bottleneck block of 3x3 1x1 3x3 1x1 3x3 convolutions .
def bottleneck_x2_block(outer_filters, bottleneck_filters):
    """Bottleneck block of 3x3, 1x1, 3x3, 1x1, 3x3 convolutions."""
    return compose(
        bottleneck_block(outer_filters, bottleneck_filters),
        DarknetConv2D_BN_Leaky(bottleneck_filters, (1, 1)),
        DarknetConv2D_BN_Leaky(outer_filters, (3, 3)))
def bottleneck_x2_block ( outer_filters , bottleneck_filters ) : return compose ( bottleneck_block ( outer_filters , bottleneck_filters ) , DarknetConv2D_BN_Leaky ( bottleneck_filters , ( 1 , 1 ) ) , DarknetConv2D_BN_Leaky ( outer_filters , ( 3 , 3 ) ) )