'Represent a (key, value) as hypertext link
@param k: the key (dvr_case_activity.id)
@param v: the representation of the key
@param row: the row with this key'

def link(self, k, v, row=None):

    beneficiary = row.pr_person
    url = URL(c='dvr', f='person', args=[beneficiary.id, 'case_activity', k], extension='')
    return A(v, _href=url)
