def demo_combineFeatures_add(rootComp: adsk.fusion.Design.rootComponent):
# Have the two bodies selected.
targetBody = _ui.selectEntity('Select a body', 'Bodies').entity
toolBody = _ui.selectEntity('Select Bodies', 'Bodies').entity
# Define the required inputs and create te combine feature.
combineFeatures = rootComp.features.combineFeatures
tools = adsk.core.ObjectCollection.create()
tools.add(toolBody)
input: adsk.fusion.CombineFeatureInput = combineFeatures.createInput(targetBody, tools)
input.isNewComponent = False
input.isKeepToolBodies = False
input.operation = adsk.fusion.FeatureOperations.JoinFeatureOperation
combineFeature = combineFeatures.add(input)