code: def append(self, newContent, keep=True):
          
          content = self.__content + newContent
          if keep:
              self.__content = content
  
          if self.__needsRewrite:
              """
              Replace the content of the file.
              A temporary file is used to avoid loss of data through an interrupt.
              """
              tmpFilename = self.filename + ".tmp"
  
              util.write_file(content, tmpFilename)
  
              os.rename(tmpFilename, self.filename)
          else:
              with open(self.filename, "a") as file:
                  file.write(newContent)
  
          self.__needsRewrite = not keep
docs: Add content to the represented file.
          If keep is False, the new content will be forgotten during the next call
          to this method.