    # File lib/chef/knife/core/cookbook_scm_repo.rb, line 72
          def prepare_to_import(cookbook_name)
            branch = "chef-vendor-#{cookbook_name}"
            if branch_exists?(branch)
              ui.info("Pristine copy branch (#{branch}) exists, switching to it.")
              git("checkout #{branch}")
            else
              ui.info("Creating pristine copy branch #{branch}")
              git("checkout -b #{branch}")
            end
          end