Don't show substitutions with "N" (don't print) flag (issue #118)

.idea/misc.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.7 (school-apps)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.6 (school-apps)" project-jdk-type="Python SDK" />
   <component name="PyCharmProfessionalAdvertiser">
     <option name="shown" value="true" />
   </component>

.idea/school-apps.iml

@@ -17,7 +17,7 @@
       <sourceFolder url="file://$MODULE_DIR$/schoolapps" isTestSource="false" />
       <excludeFolder url="file://$MODULE_DIR$/venv" />
     </content>
-    <orderEntry type="jdk" jdkName="Python 3.7 (school-apps)" jdkType="Python SDK" />
+    <orderEntry type="jdk" jdkName="Python 3.6 (school-apps)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="jquery-3.2.1" level="application" />
     <orderEntry type="module" module-name="bwinf-36-2" />

schoolapps/untisconnect/sub.py

@@ -318,8 +318,8 @@ def get_header_information(subs, date):
 
 def get_substitutions_by_date(date):
     subs_raw = run_default_filter(
-        run_using(models.Substitution.objects.filter(date=date_to_untis_date(date), deleted=0).order_by("classids",
-                                                                                                        "lesson")),
+        run_using(models.Substitution.objects.filter(date=date_to_untis_date(date), deleted=0).exclude(
+            flags__contains="N").order_by("classids", "lesson")),
         filter_term=False)
 
     subs = row_by_row_helper(subs_raw, Substitution)