from abc import ABC, abstractmethod
import numpy as np
import six

class BaseMixin(ABC):

	@abstractmethod
	def get_example(self, i):
		s = super(BaseMixin, self)
		if hasattr(s, "get_example"):
			return s.get_example(i)

	def __getitem__(self, index):
		if isinstance(index, slice):
			current, stop, step = index.indices(len(self))
			return [self.get_example(i) for i in
					six.moves.range(current, stop, step)]
		elif isinstance(index, list) or isinstance(index, np.ndarray):
			return [self.get_example(i) for i in index]
		else:
			return self.get_example(index)