Prior to dequeueing any cells, call this method or the registerNib:forCellReuseIdentifier: method to tell the table view how to create new cells. If a cell of the specified type is not currently in a reuse queue, the table view uses the provided information to create a new cell object automatically.
If you previously registered a class or nib file with the same reuse identifier, the class you specify in the cellClass parameter replaces the old entry. You may specify nil for cellClass if you want to unregister the class from the specified reuse identifier.