docs: def parse(timestamp, utc=False, produce_naive=False):
      '''
      Parse an :RFC:`3339`-formatted timestamp and return a
      `datetime.datetime`.
  
      If the timestamp is presented in UTC, then the `tzinfo` parameter of the
      returned `datetime` will be set to `pytz.utc`.
  
      >>> parse('2009-01-01T10:01:02Z')
      datetime.datetime(2009, 1, 1, 10, 1, 2, tzinfo=<UTC>)
  
      Otherwise, a `tzinfo` instance is created with the appropriate offset, and
      the `tzinfo` parameter of the returned `datetime` is set to that value.
  
      >>> parse('2009-01-01T14:01:02-04:00')
      datetime.datetime(2009, 1, 1, 14, 1, 2, tzinfo=<UTC-04:00>)
  
      However, if `parse()`  is called with `utc=True`, then the returned
      `datetime` will be normalized to UTC (and its tzinfo parameter set to
      `pytz.utc`), regardless of the input timezone.
  
      >>> parse('2009-01-01T06:01:02-04:00', utc=True)
      datetime.datetime(2009, 1, 1, 10, 1, 2, tzinfo=<UTC>)
  
      The input is strictly required to conform to :RFC:`3339`, and appropriate
      exceptions are thrown for invalid input.
  
      >>> parse('2009-01-01T06:01:02')
      Traceback (most recent call last):
      ...
      ValueError: timestamp does not conform to RFC 3339
  
      >>> parse('2009-01-01T25:01:02Z')
      Traceback (most recent call last):
      ...
      ValueError: hour must be in 0..23
  
      '''
  
      parse_re = re.compile(r'''^(?:(?:(?P<date_fullyear>[0-9]{4})\-(?P<date_month>[0-9]{2})\-(?P<date_mday>[0-9]{2}))T(?:(?:(?P<time_hour>[0-9]{2})\:(?P<time_minute>[0-9]{2})\:(?P<time_second>[0-9]{2})(?P<time_secfrac>(?:\.[0-9]{1,}))?)(?P<time_offset>(?:Z|(?P<time_numoffset>(?P<time_houroffset>(?:\+|\-)[0-9]{2})\:(?P<time_minuteoffset>[0-9]{2}))))))$''',
                            re.I | re.X)
  
      match = parse_re.match(timestamp)
  
      if match is not None:
          if match.group('time_offset') in ["Z", "z", "+00:00", "-00:00"]:
              if produce_naive is True:
                  tzinfo = None
              else:
                  tzinfo = pytz.utc
          else:
              if produce_naive is True:
                  raise ValueError("cannot produce a naive datetime from " +
                                   "a local timestamp")
              else:
                  tzinfo = FixedOffset(int(match.group('time_houroffset')),
                                       int(match.group('time_minuteoffset')))
  
          secfrac = match.group('time_secfrac')
          if secfrac is None:
              microsecond = 0
          else:
              microsecond = int(round(float(secfrac) * 1000000))
  
          dt_out = datetime(year=int(match.group('date_fullyear')),
                            month=int(match.group('date_month')),
                            day=int(match.group('date_mday')),
                            hour=int(match.group('time_hour')),
                            minute=int(match.group('time_minute')),
                            second=int(match.group('time_second')),
                            microsecond=microsecond,
                            tzinfo=tzinfo)
  
          if utc:
              dt_out = dt_out.astimezone(pytz.utc)
  
          return dt_out
      else:
          raise ValueError("timestamp does not conform to RFC 3339")