old_contents: from os import path
  
  from .bottle import Bottle, view, request
  from cleaver .backend import CleaverBackend
  
  app = Bottle()
  def __t(p):
      return path.join(
          path.dirname(path.abspath(__file__)),
          'views',
          p
      )
  
  
  def format_percentage(f):
      return '{:.2%}'.format(f) if f else '-'
  
  
  @app.route('/')
  @view(__t('index'))
  def index():
      return dict(
          backend=request.environ['cleaver.backend'],
          percentage=format_percentage
      )
  
  
  class CleaverWebUI(object):
  
      def __init__(self, backend, **kw):
          """
          A WSGI app used to view statistics on Cleaver experiments.
  
          :param backend any implementation of
                            ``backend.CleaverBackend``
          """
          self.app = app
  
          if not isinstance(backend, CleaverBackend):
              raise RuntimeError(
                  '%s must implement cleaver.backend.CleaverBackend' % backend
              )
  
          self.backend = backend
  
      def __call__(self, environ, start_response):
          environ['cleaver.backend'] = self.backend
          return self.app(environ, start_response)
  
new_contents: from os import path
  
  from .bottle import Bottle, view, request
  from cleaver .backend import CleaverBackend
  
  app = Bottle()
  
  
  def __t(p):
      return path.join(
          path.dirname(path.abspath(__file__)),
          'views',
          p
      )
  
  
  def format_percentage(f):
      return '{:.2%}'.format(f) if f else '-'
  
  
  @app.route('/')
  @view(__t('index'))
  def index():
      return dict(
          backend=request.environ['cleaver.backend'],
          percentage=format_percentage
      )
  
  
  class CleaverWebUI(object):
  
      def __init__(self, backend, **kw):
          """
          A WSGI app used to view statistics on Cleaver experiments.
  
          :param backend any implementation of
                            ``backend.CleaverBackend``
          """
          self.app = app
  
          if not isinstance(backend, CleaverBackend):
              raise RuntimeError(
                  '%s must implement cleaver.backend.CleaverBackend' % backend
              )
  
          self.backend = backend
  
      def __call__(self, environ, start_response):
          environ['cleaver.backend'] = self.backend
          return self.app(environ, start_response)
  
subject: Fix more pep8 issues.