    paper.requireView(cell)

Ensure that the view associated with the `cell` model is attached to the DOM and that it is updated.

This function finds the view by the cell model. If the view is not part of the paper's DOM (e.g. because it was outside the paper viewport), this function attaches it. Additionally, the view is updated to reflect any changes that may have been done on the cell model in the meantime.

Certain CellView methods require the view to be updated and present in the DOM to function properly (e.g. elementView.getBBox/linkView.getBBox). In `async` papers, you should precede calls to these methods with this function to guard against inconsistencies.