text: import logging
  from abc import ABCMeta
  
  import numpy as np
  from pandas import Timestamp
  
  
  class BaseSample(metaclass=ABCMeta):
      @classmethod
      def do_sample(cls, metric, value=np.nan):
          logging.info('sampling metric: "%s"' % (metric,))
          return np.array([metric, value, Timestamp.now()])
  