I get this error in the ruby console:

Error: #<TypeError: wrong argument type (expected Sketchup::Entity or Array of Sketchup::Entity)>
c:/users/kasutaja/appdata/roaming/sketchup/sketchup 2018/sketchup/plugins/followandrotate_cn.rbs:42:in add' c:/users/kasutaja/appdata/roaming/sketchup/sketchup 2018/sketchup/plugins/followandrotate_cn.rbs:42:in wikii_push_pull'
c:/users/kasutaja/appdata/roaming/sketchup/sketchup 2018/sketchup/plugins/followandrotate_cn.rbs:109:in block in <main>' SketchUp:1:in call'