Fix error when editing the review component blocks

problem_builder/mixins.py

 from lazy import lazy
 from xblock.fields import String, Boolean, Float, Scope, UNIQUE_ID
+from xblock.fragment import Fragment
 from xblockutils.helpers import child_isinstance
 from xblockutils.resources import ResourceLoader
 
@@ -167,3 +168,11 @@ class QuestionMixin(EnumerableChildMixin):
         decorative elements/instructions.
         """
         return self.mentoring_view(context)
+
+
+class NoSettingsMixin(object):
+    """ Mixin for an XBlock that has no settings """
+
+    def studio_view(self, _context=None):
+        """ Studio View """
+        return Fragment(u'<p>{}</p>'.format(self._("This XBlock does not have any settings.")))

problem_builder/step_review.py

@@ -28,7 +28,7 @@ from xblockutils.studio_editable import (
     NestedXBlockSpec, StudioEditableXBlockMixin, StudioContainerWithNestedXBlocksMixin, XBlockWithPreviewMixin
 )
 
-from .mixins import XBlockWithTranslationServiceMixin
+from .mixins import XBlockWithTranslationServiceMixin, NoSettingsMixin
 
 
 log = logging.getLogger(__name__)
@@ -133,7 +133,7 @@ class ConditionalMessageBlock(
 
 
 @XBlock.needs("i18n")
-class ScoreSummaryBlock(XBlockWithTranslationServiceMixin, XBlockWithPreviewMixin, XBlock):
+class ScoreSummaryBlock(XBlockWithTranslationServiceMixin, XBlockWithPreviewMixin, NoSettingsMixin, XBlock):
     """
     Summarize the score that the student earned.
     """
@@ -174,7 +174,7 @@ class ScoreSummaryBlock(XBlockWithTranslationServiceMixin, XBlockWithPreviewMixi
 
 
 @XBlock.needs("i18n")
-class PerQuestionFeedbackBlock(XBlockWithTranslationServiceMixin, XBlockWithPreviewMixin, XBlock):
+class PerQuestionFeedbackBlock(XBlockWithTranslationServiceMixin, XBlockWithPreviewMixin, NoSettingsMixin, XBlock):
     """
     Summaryize the score that the student earned.
     """
@@ -210,7 +210,11 @@ class PerQuestionFeedbackBlock(XBlockWithTranslationServiceMixin, XBlockWithPrev
 
 @XBlock.needs("i18n")
 class ReviewStepBlock(
-    StudioContainerWithNestedXBlocksMixin, XBlockWithTranslationServiceMixin, XBlockWithPreviewMixin, XBlock
+    StudioContainerWithNestedXBlocksMixin,
+    XBlockWithTranslationServiceMixin,
+    XBlockWithPreviewMixin,
+    NoSettingsMixin,
+    XBlock
 ):
     """
     A dedicated step for reviewing results as the last step of a Step Builder sequence.
@@ -275,10 +279,6 @@ class ReviewStepBlock(
 
     mentoring_view = student_view
 
-    def studio_view(self, _context=None):
-        """ Studio View """
-        return Fragment(u'<p>{}</p>'.format(self._("This XBlock does not have any settings.")))
-
     def author_edit_view(self, context):
         """
         Add some HTML to the author view that allows authors to add child blocks.