importing secop.asynconn should not fail when pyserial is not available Change-Id: I9d06e66cf4ab9e1ad200e8d176b4a3a0e50496c7 Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/23035 Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de> Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>