def ab_pull_edge(monolayer, cell_edges, radial_tension, distributed=False):
    """Adds a linear tension to the apical-to-basal edges
    of a cell
    """
    if distributed:
        new_tension = radial_tension / len(cell_edges)
    else:
        new_tension = radial_tension
    monolayer.edge_df.loc[cell_edges, 'line_tension'] += new_tension
