code: def _create_ayjid(aulast=None, auinit=None, date=None, jtitle=None, **kwargs):
      
      if aulast is None:
          aulast = ''
      elif isinstance(aulast, list):
          aulast = aulast[0]
  
      if auinit is None:
          auinit = ''
      elif isinstance(auinit, list):
          auinit = auinit[0]
  
      if date is None:
          date = ''
  
      if jtitle is None:
          jtitle = ''
  
      ayj = aulast + ' ' + auinit + ' ' + unicode(date) + ' ' + jtitle
  
      if ayj == '   ':
          ayj = 'Unknown paper'
  
      return ayj.upper()
docs: Convert aulast, auinit, and jtitle into the fuzzy identifier ayjid
      Returns 'Unknown paper' if all id components are missing (None).
  
      Parameters
      ----------
      Kwargs : dict
          A dictionary of keyword arguments.
      aulast : string
          Author surname.
      auinit: string
          Author initial(s).
      date : string
          Four-digit year.
      jtitle : string
          Title of the journal.
  
      Returns
      -------
      ayj : string
          Fuzzy identifier ayjid, or 'Unknown paper' if all id components are
          missing (None).