code: def install_programmer(programmer_id, programmer_options, replace_existing=False):
      
      doaction = 0
      if programmer_id in programmers().keys():
          log.debug('programmer already exists: %s', programmer_id)
          if replace_existing:
              log.debug('remove programmer: %s', programmer_id)
              remove_programmer(programmer_id)
              doaction = 1
      else:
          doaction = 1
  
      if doaction:
          lines = bunch2properties(programmer_id, programmer_options)
          programmers_txt().write_lines([''] + lines, append=1)
docs: install programmer in programmers.txt.
  
      :param programmer_id: string identifier
      :param programmer_options: dict like
      :param replace_existing: bool
      :rtype: None