I need understand the proof of this Corollary given, attributed to Andrew Thomason,.
Let $G$ be a multigraph, let $u, u \in V$$u, v \in V$, and suppose that $d ( w )$ is odd for each vertex $w \in V-$ { $u,v$ }. Then the number of Hamiltonian paths in $G$ from $u$ to $v$ is even.
I read this 'proof' but I don't understand the end.