If a vehicle is driving in the left lane on a motorway because it has overtaken, must it return immediately to the right lane?

Explanation
When overtaking and driving in the left lane, once the other vehicle has been passed, the driver should signal their lateral displacement to the right and return to the right lane gradually and safely, provided the lane is free and traffic conditions permit it. You should not swerve or make abrupt movements to return to the right lane.
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