def demo_filletFeatures_add(rootComp: adsk.fusion.Component):
# Have an edge selected.
edge = _ui.selectEntity('Select an edge', 'Edges').entity
edgesToFillet = adsk.core.ObjectCollection.create()
# Define the required input.
edgesToFillet.add(edge)
filletFeatures = rootComp.features.filletFeatures
input = filletFeatures.createInput()
radius = adsk.core.ValueInput.createByReal(2)
isTangentChain = True
input.edgeSetInputs.addConstantRadiusEdgeSet(edgesToFillet, radius, isTangentChain)
# Create the fillet.
filletFeature = filletFeatures.add(input)