def expire(url)
      if url == :all
        if store.respond_to?(:keys)
          urls.each{ |u| expire(u) }
        else
          raise(NoMethodError, "The Geocoder cache store must implement `#keys` for `expire(:all)` to work")
        end
      else
        expire_single_url(url)
      end
    end
def expire(url)
      if url == :all
        if store.respond_to?(:keys)
          urls.each{ |u| expire(u) }
        else
          raise(NoMethodError, "The Geocoder cache store must implement `#keys` for `expire(:all)` to work")
        end
      else
        expire_single_url(url)
      end
    end
Delete cache entry for given URL,
 or pass <tt>:all</tt> to clear all URLs.