[Relay OP] Check failed: type_code_ == kDLInt (4 vs. 0) : expected int but got NULL

#1

I have met a problem with deformable_conv2d, here is the example code, it will end with throwing a error message 『 Check failed: type_code_ == kDLInt (4 vs. 0) : expected int but got NULL』

from tvm import relay
from tvm.relay import expr as _expr
from tvm.relay import op as _op

x = _expr.var('x', dtype='float32', shape=[1, 512, 19, 19])
kernel = _expr.var('k', dtype='float32', shape=[512, 512, 3, 3])
offset = _expr.var('offset', dtype='float32', shape=[1, 18, 19, 19])
out0 = _op.nn.deformable_conv2d(x, offset, kernel)

Is there any wrong with the code?

#2

It tunes out that the parameter channel cannot be None, after modify the code as bellow, it runs well

from tvm import relay
from tvm.relay import expr as _expr
from tvm.relay import op as _op

x = _expr.var('x', dtype='float32', shape=[1, 512, 19, 19])
kernel = _expr.var('k', dtype='float32', shape=[512, 512, 3, 3])
offset = _expr.var('offset', dtype='float32', shape=[1, 18, 19, 19])
out0 = _op.nn.deformable_conv2d(x, offset, kernel, channels=512)

But the description of this operator says channel is optional, this may cause confuses