def demo_extrudeFeaturesSymmetricExtent_add(rootComp: adsk.fusion.Design.rootComponent):
# Have a profile selected.
profile = _ui.selectEntity('Select a profile', 'Profiles').entity
# Define the required input.
extrudeFeatures = rootComp.features.extrudeFeatures
operation = adsk.fusion.FeatureOperations.NewBodyFeatureOperation
input = extrudeFeatures.createInput(profile, operation)
distance = adsk.core.ValueInput.createByString("100 mm")
isFullLength = True
input.setSymmetricExtent(distance, isFullLength)
# Create the feature.
extrudeFeature = extrudeFeatures.add(input)