code: def make_user_agent(component=None):
      
      packageinfo = pkg_resources.require("harvestingkit")[0]
      useragent = "{0}/{1}".format(packageinfo.project_name, packageinfo.version)
      if component is not None:
          useragent += " {0}".format(component)
      return useragent
docs: create string suitable for HTTP User-Agent header