def script_sha(conn, file_name)
      if (sha = SCRIPT_SHAS.get(file_name))
        return sha
      end

      sha = conn.script(:load, script_source(file_name))
      SCRIPT_SHAS.put(file_name, sha)
      sha
    end
def script_sha(conn, file_name)
      if (sha = SCRIPT_SHAS.get(file_name))
        return sha
      end

      sha = conn.script(:load, script_source(file_name))
      SCRIPT_SHAS.put(file_name, sha)
      sha
    end
Return sha of already loaded lua script or load it and return the sha

 @param [Sidekiq::RedisConnection] conn the redis connection
 @param [Symbol] file_name the name of the lua script
 @return [String] sha of the script file

 @return [String] the sha of the script