File "/tmp/.mount_electrvWsC6V/usr/lib/python3.6/site-packages/electrum/gui/qt/history_list.py", line 606, in <lambda>
    menu.addAction(_("Child pays for parent"), lambda: self.parent.cpfp(tx, child_tx))
  File "/tmp/.mount_electrvWsC6V/usr/lib/python3.6/site-packages/electrum/gui/qt/main_window.py", line 3418, in cpfp
    new_tx.set_rbf(True)