Hi Brendan,

I’ve trained up your model with my custom data, and it’s working nicely. Now I’m trying to get it converted to coreml using onnx-coreml, but I’m stuck on an unsupported operation error:

```
TypeError: Error while converting op of type: Slice. Error message: Only single axis Slice is supported now
```

EDIT: To provide more context in figuring out where this is failing, here is the log of the conversion (seems like it’s in TransitionUp?.. perhaps center_crop()?):

```
1/224: Converting Node Type Conv
2/224: Converting Node Type BatchNormalization
3/224: Converting Node Type Relu
4/224: Converting Node Type Conv
5/224: Converting Node Type Concat
6/224: Converting Node Type BatchNormalization
7/224: Converting Node Type Relu
8/224: Converting Node Type Conv
9/224: Converting Node Type Concat
10/224: Converting Node Type BatchNormalization
11/224: Converting Node Type Relu
12/224: Converting Node Type Conv
13/224: Converting Node Type Concat
14/224: Converting Node Type BatchNormalization
15/224: Converting Node Type Relu
16/224: Converting Node Type Conv
17/224: Converting Node Type Concat
18/224: Converting Node Type BatchNormalization
19/224: Converting Node Type Relu
20/224: Converting Node Type Conv
21/224: Converting Node Type MaxPool
22/224: Converting Node Type BatchNormalization
23/224: Converting Node Type Relu
24/224: Converting Node Type Conv
25/224: Converting Node Type Concat
26/224: Converting Node Type BatchNormalization
27/224: Converting Node Type Relu
28/224: Converting Node Type Conv
29/224: Converting Node Type Concat
30/224: Converting Node Type BatchNormalization
31/224: Converting Node Type Relu
32/224: Converting Node Type Conv
33/224: Converting Node Type Concat
34/224: Converting Node Type BatchNormalization
35/224: Converting Node Type Relu
36/224: Converting Node Type Conv
37/224: Converting Node Type Concat
38/224: Converting Node Type BatchNormalization
39/224: Converting Node Type Relu
40/224: Converting Node Type Conv
41/224: Converting Node Type MaxPool
42/224: Converting Node Type BatchNormalization
43/224: Converting Node Type Relu
44/224: Converting Node Type Conv
45/224: Converting Node Type Concat
46/224: Converting Node Type BatchNormalization
47/224: Converting Node Type Relu
48/224: Converting Node Type Conv
49/224: Converting Node Type Concat
50/224: Converting Node Type BatchNormalization
51/224: Converting Node Type Relu
52/224: Converting Node Type Conv
53/224: Converting Node Type Concat
54/224: Converting Node Type BatchNormalization
55/224: Converting Node Type Relu
56/224: Converting Node Type Conv
57/224: Converting Node Type Concat
58/224: Converting Node Type BatchNormalization
59/224: Converting Node Type Relu
60/224: Converting Node Type Conv
61/224: Converting Node Type MaxPool
62/224: Converting Node Type BatchNormalization
63/224: Converting Node Type Relu
64/224: Converting Node Type Conv
65/224: Converting Node Type Concat
66/224: Converting Node Type BatchNormalization
67/224: Converting Node Type Relu
68/224: Converting Node Type Conv
69/224: Converting Node Type Concat
70/224: Converting Node Type BatchNormalization
71/224: Converting Node Type Relu
72/224: Converting Node Type Conv
73/224: Converting Node Type Concat
74/224: Converting Node Type BatchNormalization
75/224: Converting Node Type Relu
76/224: Converting Node Type Conv
77/224: Converting Node Type Concat
78/224: Converting Node Type BatchNormalization
79/224: Converting Node Type Relu
80/224: Converting Node Type Conv
81/224: Converting Node Type Concat
82/224: Converting Node Type BatchNormalization
83/224: Converting Node Type Relu
84/224: Converting Node Type Conv
85/224: Converting Node Type MaxPool
86/224: Converting Node Type BatchNormalization
87/224: Converting Node Type Relu
88/224: Converting Node Type Conv
89/224: Converting Node Type Concat
90/224: Converting Node Type BatchNormalization
91/224: Converting Node Type Relu
92/224: Converting Node Type Conv
93/224: Converting Node Type Concat
94/224: Converting Node Type BatchNormalization
95/224: Converting Node Type Relu
96/224: Converting Node Type Conv
97/224: Converting Node Type Concat
98/224: Converting Node Type BatchNormalization
99/224: Converting Node Type Relu
100/224: Converting Node Type Conv
101/224: Converting Node Type Concat
102/224: Converting Node Type BatchNormalization
103/224: Converting Node Type Relu
104/224: Converting Node Type Conv
105/224: Converting Node Type Concat
106/224: Converting Node Type BatchNormalization
107/224: Converting Node Type Relu
108/224: Converting Node Type Conv
109/224: Converting Node Type MaxPool
110/224: Converting Node Type BatchNormalization
111/224: Converting Node Type Relu
112/224: Converting Node Type Conv
113/224: Converting Node Type Concat
114/224: Converting Node Type ConvTranspose
115/224: Converting Node Type Add
116/224: Converting Node Type Slice
```

On GitHub it was recommended that I “generate two concatenated slicing operations, one working on a dimension at a time” but I’m not sure where (or how, honestly) to do that. Any advice greatly appreciated!