I am using SWCS-931SD, and there is a line coil L in the test method (image) described in the catalog. What is its purpose?

I am using SWCS-931SD, and there is a line coil L in the test method (image) described in the catalog. What is its purpose?

The purpose is to increase the impedance against high frequencies with the line coil L (choke coil) so that the applied surge is not absorbed by the battery side.