old_contents: from abc import ABC, abstractmethod
  
  from plenum.common.timer import TimerService
  from stp_core.common.log import getlogger
  
  logger = getlogger()
  
  
  # TODO docs and types
  # TODO logging
  
  
  class ViewChangerDataProvider(ABC):
      @abstractmethod
      def view_no(self):
          pass
  
      @abstractmethod
      def view_change_in_progress(self):
          pass
  
  
  class ViewChanger():
  
      def __init__(self, provider: ViewChangerDataProvider, timer: TimerService):
          self.provider = provider
          self._timer = timer
  
          self.previous_view_no = None
  
      # PROPERTIES
  
      @property
      def view_no(self):
          return self.provider.view_no()
  
      @property
      def view_change_in_progress(self) -> bool:
          return self.provider.view_change_in_progress()
  
  
new_contents: from abc import ABC, abstractmethod
  
  from plenum.common.timer import TimerService
  from stp_core.common.log import getlogger
  
  logger = getlogger()
  
  
  # TODO docs and types
  # TODO logging
  
  
  class ViewChangerDataProvider(ABC):
      @abstractmethod
      def view_no(self):
          pass
  
      @abstractmethod
      def view_change_in_progress(self):
          pass
  
  
  class ViewChanger():
  
      def __init__(self, provider: ViewChangerDataProvider, timer: TimerService):
          self.provider = provider
          self._timer = timer
  
          self.previous_view_no = None
  
      # PROPERTIES
  
      @property
      def view_no(self):
          return self.provider.view_no()
  
      @property
      def view_change_in_progress(self) -> bool:
          return self.provider.view_change_in_progress()
  
subject: Make flake8 happy