DST-caused ambiguity errors on local->UTC conversion

[ssfrr]

For 1 hour every fall there's ambiguity in the local time -> UTC time conversion, because that hour repeats itself. Here's the error it throws:

Traceback (most recent call last):

 File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 114, in get_response
   response = wrapped_callback(request, *callback_args, **callback_kwargs)

 File "/usr/local/lib/python2.7/dist-packages/django/views/decorators/csrf.py", line 57, in wrapped_view
   return view_func(*args, **kwargs)

 File "/home/sfr/chain-api/chain/core/api.py", line 748, in create_view
   return cls.create_single(data, request)

 File "/home/sfr/chain-api/chain/core/api.py", line 755, in create_single
   new_resource.save()

 File "/home/sfr/chain-api/chain/core/api.py", line 545, in save
   self._obj.save()

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 545, in save
   force_update=force_update, update_fields=update_fields)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 573, in save_base
   updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 654, in _save_table
   result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 687, in _do_insert
   using=using, raw=raw)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 232, in _insert
   return insert_query(self.model, objs, fields, **kwargs)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1511, in insert_query
   return query.get_compiler(using=using).execute_sql(return_id)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 898, in execute_sql
   for sql, params in self.as_sql():

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 856, in as_sql
   for obj in self.query.objs

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 350, in get_db_prep_save
   prepared=False)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 911, in get_db_prep_value
   value = self.get_prep_value(value)

 File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 905, in get_prep_value
   value = timezone.make_aware(value, default_timezone)

 File "/usr/local/lib/python2.7/dist-packages/django/utils/timezone.py", line 304, in make_aware
   return timezone.localize(value, is_dst=None)

 File "/usr/lib/python2.7/dist-packages/pytz/tzinfo.py", line 349, in localize
   raise AmbiguousTimeError(dt)

AmbiguousTimeError: 2015-11-01 01:00:20.770599


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GET:<QueryDict: {u'sensor_id': [u'1135']}>,
POST:<QueryDict: {}>,
COOKIES:{},
META:{'CONTENT_LENGTH': '59',
u'CSRF_COOKIE': u'4Crz0mLaS9hBfQLJYz0HsZRWJzpvhCYT',
'HTTP_ACCEPT': '*/*',
'HTTP_ACCEPT_ENCODING': 'gzip, deflate',
'HTTP_AUTHORIZATION': 'Basic Y2hhaW5jb2xsZWN0b3JzOlY4VGlPRTZ5VndwaklpbTEzeWJoakE5Tw==',
'HTTP_CONNECTION': 'close',
'HTTP_HOST': 'chain-api.media.mit.edu',
'HTTP_USER_AGENT': 'python-requests/2.3.0 CPython/2.7.3 Linux/3.2.0-4-amd64',
'HTTP_X_FORWARDED_FOR': '18.85.58.99',
'PATH_INFO': u'/scalar_data/create',
'QUERY_STRING': 'sensor_id=1135',
'RAW_URI': '/scalar_data/create?sensor_id=1135',
'REMOTE_ADDR': '18.85.58.99',
'REMOTE_PORT': '80',
'REQUEST_METHOD': 'POST',
'SCRIPT_NAME': u'',
'SERVER_NAME': 'chain-api.media.mit.edu',
'SERVER_PORT': '80',
'SERVER_PROTOCOL': 'HTTP/1.0',
'SERVER_SOFTWARE': 'gunicorn/18.0',
'gunicorn.socket': <socket._socketobject object at 0x7f8749628f30>,
'wsgi.errors': <open file '<stderr>', mode 'w' at 0x7f8752f4e1e0>,
'wsgi.file_wrapper': <class gunicorn.http.wsgi.FileWrapper at 0x7f87508061f0>,
'wsgi.input': <gunicorn.http.body.Body object at 0x7f87480e7910>,
'wsgi.multiprocess': True,
'wsgi.multithread': False,
'wsgi.run_once': False,
'wsgi.url_scheme': 'http',
'wsgi.version': (1, 0)}>