TypeError when using RegexValidator

[Bouke]

I have a RegexValidator defined as:

code_validator = RegexValidator('[A-Z]{2}-\d{5}', code='incorrect')

and trying to use it like:

class MyField(serializers.RelatedField):
    default_validators = [code_validator]

However, this fails with the stack trace below.

Traceback:
File "/django/core/handlers/base.py" in get_response
  140.                     response = response.render()
File "/django/template/response.py" in render
  105.             self.content = self.rendered_content
File "/rest_framework/response.py" in rendered_content
  59.         ret = renderer.render(self.data, media_type, context)
File "/rest_framework/renderers.py" in render
  524.         post_form = self._get_form(view, 'POST', request)
File "/rest_framework/renderers.py" in _get_form
  417.             return self.get_form(view, method, request)
File "/rest_framework/renderers.py" in get_form
  449.         serializer = view.get_serializer(instance=obj)
File "/rest_framework/generics.py" in get_serializer
  78.                                 many=many, partial=partial, context=context)
File "/rest_framework/serializers.py" in __init__
  159.         self.fields = self.get_fields()
File "/rest_framework/serializers.py" in get_fields
  191.         base_fields = copy.deepcopy(self.base_fields)
File "/python2.7/copy.py" in deepcopy
  174.                 y = copier(memo)
File "/django/utils/datastructures.py" in __deepcopy__
  138.                                for key, value in self.items()])
File "/python2.7/copy.py" in deepcopy
  190.                 y = _reconstruct(x, rv, 1, memo)
File "/python2.7/copy.py" in _reconstruct
  334.             state = deepcopy(state, memo)
File "/python2.7/copy.py" in deepcopy
  163.         y = copier(x, memo)
File "/python2.7/copy.py" in _deepcopy_dict
  257.         y[deepcopy(key, memo)] = deepcopy(value, memo)
File "/python2.7/copy.py" in deepcopy
  163.         y = copier(x, memo)
File "/python2.7/copy.py" in _deepcopy_list
  230.         y.append(deepcopy(a, memo))
File "/python2.7/copy.py" in deepcopy
  190.                 y = _reconstruct(x, rv, 1, memo)
File "/python2.7/copy.py" in _reconstruct
  334.             state = deepcopy(state, memo)
File "/python2.7/copy.py" in deepcopy
  163.         y = copier(x, memo)
File "/python2.7/copy.py" in _deepcopy_dict
  257.         y[deepcopy(key, memo)] = deepcopy(value, memo)
File "/python2.7/copy.py" in deepcopy
  174.                 y = copier(memo)

Exception Type: TypeError at /.../
Exception Value: cannot deepcopy this pattern object