old_contents: from django.utils.translation import ugettext_lazy as _
  from django.core.validators import ValidationError
  
  class MutuallyExclusiveWithField(object):
      def __init__(self, other_field_name, error_message=_("Please enter one and only one of those fields.")):
          self.other, self.error_message = other_field_name, error_message
          self.always_test = True
  
      def __call__(self, field_data, all_data):
          if all_data.get(self.other, False) and field_data or \
             not all_data.get(self.other, False) and not field_data:
              raise ValidationError, self.error_message
  
  class ValidateIfFieldsSame(object):
      def __init__(self, other_field, error_message=_("These fields can not be the same.")):
          self.other_field = other_field
          self.always_test = True
          self.error_message = error_message
      
      def __call__(self, field_data, all_data):
          if field_data == all_data[self.other_field]:
              raise ValidationError, self.error_message
new_contents: from django.utils.translation import ugettext_lazy as _
  from django.core.exceptions import ValidationError
  
  class MutuallyExclusiveWithField(object):
      def __init__(self, other_field_name, error_message=_("Please enter one and only one of those fields.")):
          self.other, self.error_message = other_field_name, error_message
          self.always_test = True
  
      def __call__(self, field_data, all_data):
          if all_data.get(self.other, False) and field_data or \
             not all_data.get(self.other, False) and not field_data:
              raise ValidationError, self.error_message
  
  class ValidateIfFieldsSame(object):
      def __init__(self, other_field, error_message=_("These fields can not be the same.")):
          self.other_field = other_field
          self.always_test = True
          self.error_message = error_message
      
      def __call__(self, field_data, all_data):
          if field_data == all_data[self.other_field]:
              raise ValidationError, self.error_message
  
subject: Fix a broken import. Closes #1093