diff --git a/server/books/schema/mutations/utils.py b/server/books/schema/mutations/utils.py
index fcbd0c3d..2f52bcf9 100644
--- a/server/books/schema/mutations/utils.py
+++ b/server/books/schema/mutations/utils.py
@@ -15,6 +15,10 @@ from assignments.models import Assignment
 from books.models import ContentBlock
 
 
+class AssignmentParameterException(Exception):
+    pass
+
+
 def newlines_to_paragraphs(text):
     parts = re.split(r'[\r\n]+', text)
     paragraphs = ['<p>{}</p>'.format(p.strip()) for p in parts]
@@ -32,7 +36,7 @@ ALLOWED_BLOCKS = (
 )
 
 
-def handle_content_block(content, context, module, allowed_blocks=ALLOWED_BLOCKS):
+def handle_content_block(content, context=None, module=None, allowed_blocks=ALLOWED_BLOCKS):
     # todo: add all the content blocks
     # todo: sanitize user inputs!
     if content['type'] not in allowed_blocks:
@@ -45,6 +49,10 @@ def handle_content_block(content, context, module, allowed_blocks=ALLOWED_BLOCKS
                 'text': newlines_to_paragraphs(bleach.clean(content['value']['text'], strip=True))
             }}
     elif content['type'] == 'assignment':
+        if module is None:
+            raise AssignmentParameterException('Module is missing for assignment')  # todo: define better exception
+        if context is None:
+            raise AssignmentParameterException('Context is missing for assignment')
         assignment = Assignment.objects.create(
             title=content['value']['title'],
             assignment=content['value']['assignment'],