code: def _tz_offset_string(offset):
          
  
          s = ""
          io = int(offset)
          if io == 0:
              s += "Z"
          else:
              if -1440 < io < 1440:
                  ho = abs(io) / 60
                  mo = abs(io) % 60
  
                  s += "%c%02u" % ("+" if io > 0 else "-", ho)
                  if mo != 0:
                      s += ":%02u" % mo
  
              else:
                  raise ValueError("Timezone `offset` (%u) out of range "
                                   "-1439 to +1439 minutes" % io)
          return s
docs: (Internal) Convert TZ offset in minutes east to string.