text: #!/usr/bin/env python
  
  # Copyright 2017 The Kubernetes Authors.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import datetime
  import math
  import re
  
  
  class TimezoneInfo(datetime.tzinfo):
      def __init__(self, h, m):
          self._name = "UTC"
          if h != 0 and m != 0:
              self._name += "%+03d:%2d" % (h, m)
          self._delta = datetime.timedelta(hours=h, minutes=math.copysign(m, h))
  
      def utcoffset(self, dt):
          return self._delta
  
      def tzname(self, dt):
          return self._name
  
      def dst(self, dt):
          return datetime.timedelta(0)
  
  
  UTC = TimezoneInfo(0, 0)
  
  # ref https://www.ietf.org/rfc/rfc3339.txt
  _re_rfc3339 = re.compile(r"(\d\d\d\d)-(\d\d)-(\d\d)"        # full-date
                           r"[ Tt]"                           # Separator
                           r"(\d\d):(\d\d):(\d\d)([.,]\d+)?"  # partial-time
                           r"([zZ ]|[-+]\d\d?:\d\d)?",        # time-offset
                           re.VERBOSE + re.IGNORECASE)
  _re_timezone = re.compile(r"([-+])(\d\d?):?(\d\d)?")
  
  
  def parse_rfc3339(s):
      if isinstance(s, datetime.datetime):
          # no need to parse it, just make sure it has a timezone.
          if not s.tzinfo:
              return s.replace(tzinfo=UTC)
          return s
      groups = _re_rfc3339.search(s).groups()
      dt = [0] * 7
      for x in range(6):
          dt[x] = int(groups[x])
      if groups[6] is not None:
          dt[6] = int(groups[6])
      tz = UTC
      if groups[7] is not None and groups[7] != 'Z' and groups[7] != 'z':
          tz_groups = _re_timezone.search(groups[7]).groups()
          hour = int(tz_groups[1])
          minute = 0
          if tz_groups[0] == "-":
              hour *= -1
          if tz_groups[2]:
              minute = int(tz_groups[2])
          tz = TimezoneInfo(hour, minute)
      return datetime.datetime(
          year=dt[0], month=dt[1], day=dt[2],
          hour=dt[3], minute=dt[4], second=dt[5],
          microsecond=dt[6], tzinfo=tz)
  
  
  def format_rfc3339(date_time):
      if date_time.tzinfo is None:
          date_time = date_time.replace(tzinfo=UTC)
      date_time = date_time.astimezone(UTC)
      return date_time.strftime('%Y-%m-%dT%H:%M:%SZ')
  