code: def format_who_when(fields):
      
      offset = fields[3]
      if offset < 0:
          offset_sign = b'-'
          offset = abs(offset)
      else:
          offset_sign = b'+'
      offset_hours = offset // 3600
      offset_minutes = offset // 60 - offset_hours * 60
      offset_str = offset_sign + ('%02d%02d' % (offset_hours, offset_minutes)).encode('ascii')
      name = fields[0]
  
      if name == b'':
          sep = b''
      else:
          sep = b' '
  
      name = utf8_bytes_string(name)
  
      email = fields[1]
  
      email = utf8_bytes_string(email)
  
      return b''.join((name, sep, b'<', email, b'> ', ("%d" % fields[2]).encode('ascii'), b' ', offset_str))
docs: Format a tuple of name,email,secs-since-epoch,utc-offset-secs as a string.