[docs]deflogin()->WebClient:"""Authenticate using the Slack API."""try:fromslack_sdkimportWebClientexceptImportErrorase:raiseImportError("Cannot import slack_sdk. Please install the package with \ `pip install slack_sdk`.")fromeif"SLACK_BOT_TOKEN"inos.environ:token=os.environ["SLACK_BOT_TOKEN"]client=WebClient(token=token)logger.info("slack login success")returnclientelif"SLACK_USER_TOKEN"inos.environ:token=os.environ["SLACK_USER_TOKEN"]client=WebClient(token=token)logger.info("slack login success")returnclientelse:logger.error("Error: The SLACK_BOT_TOKEN or SLACK_USER_TOKEN \ environment variable have not been set.")
UTC_FORMAT="%Y-%m-%dT%H:%M:%S%z""""UTC format for datetime objects."""