old_contents: #!/usr/bin/python
  # -*- coding: utf-8 -*-
  
  # thumbor imaging service
  # https://github.com/thumbor/thumbor/wiki
  
  # Licensed under the MIT license:
  # http://www.opensource.org/licenses/mit-license
  # Copyright (c) 2011 globo.com thumbor@googlegroups.com
  
  from thumbor.filters import BaseFilter, filter_method
  
  
  class Filter(BaseFilter):
  
      @filter_method(BaseFilter.DecimalNumber)
      def proportion(self, value):
          source_width, source_height = self.context.request.engine.size
  
          new_width = source_width * value
          new_height = source_height * value
  
          if new_width <= 0 or new_height <= 0:
              return
  
          self.engine.resize(new_width, new_height)
          
  
new_contents: #!/usr/bin/python
  # -*- coding: utf-8 -*-
  
  # thumbor imaging service
  # https://github.com/thumbor/thumbor/wiki
  
  # Licensed under the MIT license:
  # http://www.opensource.org/licenses/mit-license
  # Copyright (c) 2011 globo.com thumbor@googlegroups.com
  
  from thumbor.filters import BaseFilter, filter_method
  
  
  class Filter(BaseFilter):
  
      @filter_method(BaseFilter.DecimalNumber)
      def proportion(self, value):
          source_width, source_height = self.context.request.engine.size
  
          new_width = source_width * value
          new_height = source_height * value
  
          if new_width <= 0 or new_height <= 0:
              return
  
          self.engine.resize(new_width, new_height)
  
subject: Remove trailing whitespaces