code: def prepend(object)
        sub_chain_a_tail = coerce object
  
        if chain_head?
          sub_chain_a_tail.split_after_and_insert
          sub_chain_a_tail.append self
  
          return chain_head
        end
  
        target_chain = chain_head
  
        sub_chain_a_head = sub_chain_a_tail.split_after_and_insert target_chain
  
        prev!.next = sub_chain_a_head
        sub_chain_a_head.prev = prev!
  
        sub_chain_a_tail.next = self
        self.prev = sub_chain_a_tail
  
        sub_chain_a_head
      end
docs: rubocop:enable Metrics/MethodLength
   rubocop:disable Metrics/MethodLength