code: def fix_e711(self, result):
          
          (line_index, offset, target) = get_index_offset_contents(result,
                                                                   self.source)
  
          right_offset = offset + 2
          if right_offset >= len(target):
              return []
  
          left = target[:offset].rstrip()
          center = target[offset:right_offset]
          right = target[right_offset:].lstrip()
  
          if not right.startswith('None'):
              return []
  
          if center.strip() == '==':
              new_center = 'is'
          elif center.strip() == '!=':
              new_center = 'is not'
          else:
              return []
  
          self.source[line_index] = ' '.join([left, new_center, right])
docs: Fix comparison with None.