Liveryman’s lien.

It shall be lawful for all persons keeping or boarding any animals at livery within the District, under any agreement with the owner thereof, to detain such animals until all charges under such agreement for the care, keep, or board of such animals shall have been paid; provided, however, that before enforcing the lien hereby given notice in writing shall be given to such owner in person or by registered mail at his last-known place of residence of the amount of such charges and the intention to detain such animal or animals until such charges shall be paid.