class Dependabot::FileParsers::Base::DependencySet

def +(other)
  raise ArgumentError, "must be a DependencySet" unless other.is_a?(DependencySet)
  other_names = other.dependencies.map(&:name)
  other_names.each do |name|
    all_versions = other.all_versions_for_name(name)
    all_versions.each { |dep| self << dep }
  end
  self
end