def validate_referenced_tasks(task_name)
        validate_presence_of_reference_tasks(task_name, 'starts', Array) &&
        validate_presence_of_reference_tasks(task_name, 'starts_parallel', Array) &&
        validate_presence_of_reference_tasks(task_name, 'starts_manually', Array) &&
        validate_presence_of_reference_tasks(task_name, 'starts_with_params', Hash) &&