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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def voltage_delta_stub(grid, tree, main_branch_node, stub_node, r_preceeding, x_preceedig):
 """ Determine voltage for stub branches Parameters grid : LVGridDing0 Ding0 grid object tree : :networkx:`NetworkX Graph Obj< >` Tree of grid topology main_branch_node : graph node Node of main branch that stub branch node in connected to main_branch : dict Nodes of main branch r_preceeding : float Resitance of preceeding grid x_preceeding : float Reactance of preceeding grid Return ------ :any:`float` Delta voltage for node """

    cos_phi_load = cfg_ding0.get('assumptions', 'cos_phi_load')
    cos_phi_feedin = cfg_ding0.get('assumptions', 'cos_phi_gen')
    v_nom = cfg_ding0.get('assumptions', 'lv_nominal_voltage')
    omega = 2 * math.pi * 50

    stub_branch = [_ for _ in grid.graph_branches_from_node(main_branch_node) if
                   _[0] == stub_node][0][1]
    r_stub = stub_branch['branch'].type['R'] * stub_branch[
        'branch'].length / 1e3
    x_stub = stub_branch['branch'].type['L'] / 1e3 * omega * \
             stub_branch['branch'].length / 1e3
    s_max_gen = [_.capacity / cos_phi_feedin
                 for _ in tree.successors(stub_node)
                 if isinstance(_, GeneratorDing0)]
    if s_max_gen:
        s_max_gen = s_max_gen[0]
        v_delta_stub_gen = voltage_delta_vde(v_nom, s_max_gen, r_stub + r_preceeding,
                                             x_stub + x_preceedig, cos_phi_feedin)
    else:
        v_delta_stub_gen = 0

    s_max_load = [_.peak_load / cos_phi_load
                  for _ in tree.successors(stub_node)
                  if isinstance(_, LVLoadDing0)]
    if s_max_load:
        s_max_load = s_max_load[0]
        v_delta_stub_load = voltage_delta_vde(v_nom, s_max_load, r_stub + r_preceeding,
                                              x_stub + x_preceedig, cos_phi_load)
    else:
        v_delta_stub_load = 0

    return [v_delta_stub_load, v_delta_stub_gen]