text: """
  YAML serializer.
  
  Requires PyYaml (http://pyyaml.org/), but that's checked for in __init__.
  """
  
  import collections
  import decimal
  from io import StringIO
  
  import yaml
  
  from django.core.serializers.base import DeserializationError
  from django.core.serializers.python import (
      Deserializer as PythonDeserializer, Serializer as PythonSerializer,
  )
  from django.db import models
  
  # Use the C (faster) implementation if possible
  try:
      from yaml import CSafeLoader as SafeLoader
      from yaml import CSafeDumper as SafeDumper
  except ImportError:
      from yaml import SafeLoader, SafeDumper
  
  
  class DjangoSafeDumper(SafeDumper):
      def represent_decimal(self, data):
          return self.represent_scalar('tag:yaml.org,2002:str', str(data))
  
      def represent_ordered_dict(self, data):
          return self.represent_mapping('tag:yaml.org,2002:map', data.items())
  
  
  DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)
  DjangoSafeDumper.add_representer(collections.OrderedDict, DjangoSafeDumper.represent_ordered_dict)
  
  
  class Serializer(PythonSerializer):
      """Convert a queryset to YAML."""
  
      internal_use_only = False
  
      def handle_field(self, obj, field):
          # A nasty special case: base.css YAML doesn't support serialization of time
          # types (as opposed to dates or datetimes, which it does support). Since
          # we want to use the "safe" serializer for better interoperability, we
          # need to do something with those pesky times. Converting 'em to strings
          # isn't perfect, but it's better than a "!!python/time" type which would
          # halt deserialization under any other language.
          if isinstance(field, models.TimeField) and getattr(obj, field.name) is not None:
              self._current[field.name] = str(getattr(obj, field.name))
          else:
              super().handle_field(obj, field)
  
      def end_serialization(self):
          yaml.dump(self.objects, self.stream, Dumper=DjangoSafeDumper, **self.options)
  
      def getvalue(self):
          # Grandparent super
          return super(PythonSerializer, self).getvalue()
  
  
  def Deserializer(stream_or_string, **options):
      """Deserialize a stream or string of YAML data."""
      if isinstance(stream_or_string, bytes):
          stream_or_string = stream_or_string.decode()
      if isinstance(stream_or_string, str):
          stream = StringIO(stream_or_string)
      else:
          stream = stream_or_string
      try:
          yield from PythonDeserializer(yaml.load(stream, Loader=SafeLoader), **options)
      except (GeneratorExit, DeserializationError):
          raise
      except Exception as exc:
          raise DeserializationError() from exc
  