parameters: (self, index)
return_statement: return image_file
docstring: given image index, find out full path
          :param index: index of a specific image
          :return: full path of this image
docstring_summary: given image index, find out full path
          :param index: index of a specific image
          :return: full path of this image
docstring_tokens: given image index find out full path : param index : index of a specific image : return : full path of this image
function: def image_path_from_index(self, index):
          """
          given image index, find out full path
          :param index: index of a specific image
          :return: full path of this image
          """
          image_file = os.path.join(self.data_path, 'JPEGImages', index + '.jpg')
          assert os.path.exists(image_file), 'Path does not exist: {}'.format(image_file)
          return image_file
function_tokens: def image_path_from_index ( self , index ) : image_file = os . path . join ( self . data_path , 'JPEGImages' , index + '.jpg' ) assert os . path . exists ( image_file ) , 'Path does not exist: {}' . format ( image_file ) return image_file