add_sources

# File lib/bundler/lockfile_generator.rb, line 30
    def add_sources
      definition.send(:sources).lock_sources.each_with_index do |source, idx|
        out << "\n" unless idx.zero?

        # Add the source header
        out << source.to_lock

        # Find all specs for this source
        specs = definition.resolve.select {|s| source.can_lock?(s) }
        add_specs(specs)
      end
    end