  class HyperlinkedRelatedField(RelatedField):
      lookup_field = 'pk'
  
      default_error_messages = {
          'required': _("This field is required."),
          'no_match': _("Invalid hyperlink - No URL match."),
          'incorrect_match': _("Invalid hyperlink - Incorrect URL match."),
          'does_not_exist': _("Invalid hyperlink - Object does not exist."),
          'incorrect_type': _("Incorrect type. Expected URL string, received {data_type}."),
      }
  
      def __init__(self, view_name=None, **kwargs):
          assert view_name is not None, 'The `view_name` argument is required.'
          self.view_name = view_name
 
</s> remove         'required': _("This field is required."),
        'does_not_exist': _("Invalid pk \"{pk_value}\" - object does not exist."),
        'incorrect_type': _("Incorrect type. Expected pk value, received {data_type}."),
 </s> add         'required': _('This field is required.'),
        'does_not_exist': _('Invalid pk "{pk_value}" - object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected pk value, received {data_type}.'), </s> remove         'does_not_exist': _("Object with {slug_name}={value} does not exist."),
        'invalid': _("Invalid value."),
 </s> add         'does_not_exist': _('Object with {slug_name}={value} does not exist.'),
        'invalid': _('Invalid value.'), </s> remove         'required': _("This field is required."),
        'null': _("This field may not be null.")
 </s> add         'required': _('This field is required.'),
        'null': _('This field may not be null.') </s> remove     invalid_version_message = _("Invalid version in URL path.")
 </s> add     invalid_version_message = _('Invalid version in URL path.') </s> remove msgid "Invalid pk '{pk_value}' - object does not exist."
 </s> add msgid "Invalid pk \"{pk_value}\" - object does not exist."
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
  class HyperlinkedRelatedField(RelatedField):
      lookup_field = 'pk'
  
      default_error_messages = {
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
        'required': _('This field is required.'),
        'no_match': _('Invalid hyperlink - No URL match.'),
        'incorrect_match': _('Invalid hyperlink - Incorrect URL match.'),
        'does_not_exist': _('Invalid hyperlink - Object does not exist.'),
        'incorrect_type': _('Incorrect type. Expected URL string, received {data_type}.'),
      }
  
      def __init__(self, view_name=None, **kwargs):
          assert view_name is not None, 'The `view_name` argument is required.'
          self.view_name = view_name
keep keep keep keep replace replace replace replace replace keep keep keep keep keep
 prefer single quotes in source and double quotes in user visible strings; add some missing full stops to user visible strings 
rest_framework/relations.py