In sage.modules.genera.genus.canonical_2_adic_trains
forgets the trains of length one.
Maybe this causes further bugs.

Component: quadratic forms

Keywords: sd91

Author: Simon Brandhorst

Branch/Commit: d7fa2c4

Reviewer: David Roe

Issue created by migration from https://trac.sagemath.org/ticket/23955