<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def memory_usage(method):
 """Log memory usage before and after a method."""

  def wrapper(*args, **kwargs):
    logging.info('Memory before method %s is %s.',
                 method.__name__, runtime.memory_usage().current())
    result = method(*args, **kwargs)
    logging.info('Memory after method %s is %s',
                 method.__name__, runtime.memory_usage().current())
    return result
  return wrapper