Change the way to validate keep_num_dims attribute for new tf. (#2367)

* Change the way to validate keep_num_dims attribute for new tf.

Signed-off-by: Jay Zhang <jiz@microsoft.com>

* Fix a lint issue.

Signed-off-by: Jay Zhang <jiz@microsoft.com>

---------

Signed-off-by: Jay Zhang <jiz@microsoft.com>

Author: fatcat-z

tf2onnx/tflite_handlers/tfl_math.py

@@ -201,12 +201,10 @@ def to_tf(cls, ctx, node, **kwargs):
         separate_fused_activation_function(ctx, node)
         utils.make_sure(node.attr['weights_format'].s == b'DEFAULT',
                         "Only default weights format supported for fully connected op")
-        utils.make_sure(node.attr['keep_num_dims'].i == 0,
-                        "Only keep_num_dims=False supported for fully connected op")
         if node.attr['asymmetric_quantize_inputs'].i == 1:
             dynamic_quantize_inputs(ctx, node)
 
-        if ctx.get_rank(node.input[0]) != 2:
+        if node.attr['keep_num_dims'].i == 0 and ctx.get_rank(node.input[0]) != 2:
             # When a fullyconnected node has keep_num_dims=0 and input[0] rank > 2, the extra dims must be compressed
             utils.make_sure(ctx.get_rank(node.input[1]) == 2, "weights for FullyConnected must have rank 2")
             weights_shape = ctx.get_shape(node.input[1])[1]