<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def define_log_processors():
 """ log processors that structlog executes before final rendering """

    # these processors should accept logger, method_name and event_dict
    # and return a new dictionary which will be passed as event_dict to the next one.
    return [
        structlog.processors.TimeStamper(fmt="iso"),
        _structlog_default_keys_processor,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.StackInfoRenderer(),
        structlog.processors.format_exc_info,
    ]