code: def trigger(self, state_machine_arn, input):
      return self._client.start_execution(
          stateMachineArn=state_machine_arn, input=input
      )
  
file_path: metaflow/metaflow/plugins/aws/step_functions/step_functions_client.py
imports: from metaflow.metaflow_config import AWS_SANDBOX_ENABLED, AWS_SANDBOX_REGION, SFN_EXECUTION_LOG_GROUP_ARN
label_desc: Use image node_id 5 for calling the StepFunctionsClient obj's underlying member method code with example usage: obj.trigger(state_machine_arn, input) and returns: self