Lepton-number test of a decay channel

Sum the lepton numbers of every final particle and compare with the initial sum. For example, $e^{-}{\nu }_e{e}^{-}{e}^{+}$ has $L_e=2$, whereas $e^{-}{\bar{\nu }}_e{e}^{-}{e}^{+}$ has $L_e=0$. The two differ physically; changing a neutrino bar is not a harmless typographic simplification. Overall lepton number is conserved by the usual charged-current Standard Model amplitudes with Dirac or massless neutrinos.