class Dependabot::PullRequestCreator::MessageBuilder

def old_library_requirement(dependency)
  old_reqs =
    T.must(dependency.previous_requirements) - dependency.requirements
  gemspec =
    old_reqs.find { |r| r[:file].match?(%r{^[^/]*\.gemspec$}) }
  return gemspec.fetch(:requirement) if gemspec
  req = T.must(old_reqs.first).fetch(:requirement)
  return req if req
  dependency.previous_ref if dependency.ref_changed?
end