Help on converting scrfd model with batch size = 8

Hi there, I tried to convert scrfd model to onnx with batch size = 8. The original converting script doesn't have an option to modify batch size so I added the following code:

model = onnx.load(ori_output_file)
inputs = model.graph.input
for input in inputs:
# Checks omitted.This assumes that all inputs are tensors and have a shape with first dim.
# Add checks as needed.
dim1 = input.type.tensor_type.shape.dim[0]
# update dim to be a symbolic value
#dim1.dim_param = sym_batch_dim
# or update it to be an actual value:
dim1.dim_value = 8

But it doesn't work, so any idea about this?