def METHOD_NAME(mesh, source):
    """Define function for the current source term.
    :math:`\delta(x-pos), \int f(x) \delta(x-pos)=f(pos)=N(pos)`
    Right hand side entries will be shape functions(pos)
    """
    rhs = pg.Vector(mesh.nodeCount())
    cell = mesh.findCell(source)
    rhs.setVal(cell.N(cell.shape().rst(source)), cell.ids())
    return rhs