text: import abc
  import numpy
  from typing import Tuple, Dict
  
  
  class Device(metaclass=abc.ABCMeta):
      @abc.abstractmethod
      def get_usage_perc(self, timeslice: Tuple[int, int]) -> numpy.ndarray:
          pass
  
      @abc.abstractmethod
      def get_qd(self, timeslice: Tuple[int, int]) -> numpy.ndarray:
          pass
  
      @abc.abstractmethod
      def get_err_count(self, timeslice: Tuple[int, int]) -> numpy.ndarray:
          pass
  
  
  class NetAdapter(Device):
      def __init__(self, node: str, name: str, max_speed: int, duplex: bool = True) -> None:
          self.timestamps = None  # type: numpy.ndarray
          self.tss = None  # type: Dict[str, numpy.ndarray]
  
      def set_load(self, timestamps: numpy.ndarray, **tss: numpy.ndarray) -> None:
          pass
  
      def get_usage_perc(self, timeslice: Tuple[int, int]) -> numpy.ndarray:
          return get_slice(self.timestamps, self.tss[''])
  