Add QStringView/QByteArrayView

View types as function parameters cannot be converted in the standard
way shiboken does it:

QStringView cppArg0;
pythonToCpp(pyArg, &cppArg0);

since they reference some other data.

Introduce a new "viewOn" member to type system entry for them. It
causes the function arguments to be replaced by their viewed-on types
(stringview->string) via metatype.

Add a test in libsample and a test for QUuid::fromString(QStringView).
Test returning QStringView via QRegularExpressionMatch::capturedView().

Task-number: QTBUG-84319
Task-number: PYSIDE-1339
Task-number: PYSIDE-904
Task-number: PYSIDE-487
Change-Id: Iddb4ea268a54928d290e29012e2738772fae83f0
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

20 files changed, 144 insertions, 21 deletions

diff --git a/sources/pyside2/PySide2/QtCore/typesystem_core_common.xml b/sources/pyside2/PySide2/QtCore/typesystem_core_common.xml
index 2cbfe638b..46e3c6fe6 100644
--- a/sources/pyside2/PySide2/QtCore/typesystem_core_common.xml
+++ b/sources/pyside2/PySide2/QtCore/typesystem_core_common.xml
@@ -253,6 +253,13 @@
     </conversion-rule>
   </primitive-type>
 
+  <primitive-type name="QStringView" target-lang-api-name="PyUnicode" view-on="QString">
+    <include file-name="QStringView" location="global"/>
+    <conversion-rule>
+        <native-to-target file="../glue/qtcore.cpp" snippet="return-pyunicode"/>
+    </conversion-rule>
+  </primitive-type>
+
   <primitive-type name="QChar">
     <conversion-rule>
         <native-to-target file="../glue/qtcore.cpp" snippet="return-pyunicode-qchar"/>
@@ -2022,6 +2029,12 @@
         <inject-code class="target" position="beginning" file="../glue/qtcore.cpp" snippet="qbytearray-msetitem"/>
     </add-function>
   </value-type>
+  <primitive-type name="QByteArrayView" view-on="QByteArray" since="6.0">
+    <conversion-rule>
+        <native-to-target file="../glue/qtcore.cpp" snippet="return-pybytes"/>
+    </conversion-rule>
+  </primitive-type>
+
   <value-type name="QTextBoundaryFinder">
     <enum-type name="BoundaryReason" flags="BoundaryReasons"/>
     <enum-type name="BoundaryType"/>
diff --git a/sources/pyside2/PySide2/glue/qtcore.cpp b/sources/pyside2/PySide2/glue/qtcore.cpp
index 45e0e8c25..eb8d6dff4 100644
--- a/sources/pyside2/PySide2/glue/qtcore.cpp
+++ b/sources/pyside2/PySide2/glue/qtcore.cpp
@@ -1839,6 +1839,10 @@ int usec = PyDateTime_TIME_GET_MICROSECOND(%in);
 return PyBool_FromLong((bool)%in);
 // @snippet return-pybool
 
+// @snippet return-pybytes
+return PyBytes_FromStringAndSize(%in.constData(), %in.size());
+// @snippet return-pybytes
+
 // @snippet return-pylong
 return PyLong_FromLong(%in);
 // @snippet return-pylong
diff --git a/sources/pyside2/tests/QtCore/qregularexpression_test.py b/sources/pyside2/tests/QtCore/qregularexpression_test.py
index fb2e9c24c..50c755d0e 100644
--- a/sources/pyside2/tests/QtCore/qregularexpression_test.py
+++ b/sources/pyside2/tests/QtCore/qregularexpression_test.py
@@ -48,6 +48,7 @@ class QRegularExpressionTest(unittest.TestCase):
         match = re.match('word1 word2  word3')
         self.assertTrue(match.isValid())
         self.assertEqual(match.captured(1), 'word2')
+        self.assertEqual(match.capturedView(1), 'word2')
 
     def testMatchIterator(self):
         re = QRegularExpression('(\w+)')
diff --git a/sources/pyside2/tests/QtCore/quuid_test.py b/sources/pyside2/tests/QtCore/quuid_test.py
index da34429f9..ecb4a9562 100644
--- a/sources/pyside2/tests/QtCore/quuid_test.py
+++ b/sources/pyside2/tests/QtCore/quuid_test.py
@@ -43,7 +43,8 @@ from PySide2.QtCore import QUuid
 class QUuidTest(unittest.TestCase):
     def testFromString(self):
         uuidString = '{fc69b59e-cc34-4436-a43c-ee95d128b8c5}'
-        uuid = QUuid(uuidString)
+#       testing overload QUUid::fromString(QStringView)
+        uuid = QUuid.fromString(uuidString)
         self.assertTrue(not uuid.isNull())
         self.assertEqual(uuid.toString(), uuidString)
 
diff --git a/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp b/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
index 899d910bc..d06a338a3 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
+++ b/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
@@ -1884,6 +1884,17 @@ AbstractMetaFunction *AbstractMetaBuilderPrivate::traverseFunction(const Functio
             return nullptr;
         }
 
+        // Add view substitution for simple view types of function arguments
+        // std::string_view -> std::string for foo(std::string_view)
+        auto viewOnTypeEntry = metaType->typeEntry()->viewOn();
+        if (viewOnTypeEntry != nullptr && metaType->indirections() == 0
+            && metaType->arrayElementType() == nullptr
+            && !metaType->hasInstantiations()) {
+            auto viewOn = new AbstractMetaType(*metaType);
+            viewOn->setTypeEntry(viewOnTypeEntry);
+            metaType->setViewOn(viewOn);
+        }
+
         auto *metaArgument = new AbstractMetaArgument;
 
         metaArgument->setType(metaType);
diff --git a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
index 7d98d9ae8..edb449b04 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
+++ b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
@@ -194,10 +194,13 @@ AbstractMetaType::AbstractMetaType() :
 {
 }
 
+AbstractMetaType::AbstractMetaType(const AbstractMetaType &rhs) = default;
+
 AbstractMetaType::~AbstractMetaType()
 {
     qDeleteAll(m_children);
     m_instantiations.clear();
+    delete m_viewOn;
 }
 
 QString AbstractMetaType::package() const
@@ -449,6 +452,8 @@ QDebug operator<<(QDebug d, const AbstractMetaType *at)
                 }
             }
             d << '>';
+            if (at->viewOn())
+                d << ", views " << at->viewOn()->name();
         }
     } else {
         d << '0';
diff --git a/sources/shiboken2/ApiExtractor/abstractmetalang.h b/sources/shiboken2/ApiExtractor/abstractmetalang.h
index 648c792b3..0e187fbcf 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetalang.h
+++ b/sources/shiboken2/ApiExtractor/abstractmetalang.h
@@ -303,6 +303,7 @@ public:
     Q_DECLARE_FLAGS(ComparisonFlags, ComparisonFlag);
 
     AbstractMetaType();
+    AbstractMetaType(const AbstractMetaType &);
     ~AbstractMetaType();
 
     QString package() const;
@@ -530,6 +531,12 @@ public:
 
     bool compare(const AbstractMetaType &rhs, ComparisonFlags = {}) const;
 
+    // View on: Type to use for function argument conversion, fex
+    // std::string_view -> std::string for foo(std::string_view);
+    // cf TypeEntry::viewOn()
+    const AbstractMetaType *viewOn() const { return m_viewOn; }
+    void setViewOn(const AbstractMetaType *v) { m_viewOn = v; }
+
 private:
     TypeUsagePattern determineUsagePattern() const;
     QString formatSignature(bool minimal) const;
@@ -545,6 +552,7 @@ private:
     int m_arrayElementCount = -1;
     const AbstractMetaType *m_arrayElementType = nullptr;
     const AbstractMetaType *m_originalTemplateType = nullptr;
+    const AbstractMetaType *m_viewOn = nullptr;
     Indirections m_indirections;
 
     TypeUsagePattern m_pattern = InvalidPattern;
@@ -555,8 +563,6 @@ private:
 
     ReferenceType m_referenceType = NoReference;
     AbstractMetaTypeList m_children;
-
-    Q_DISABLE_COPY(AbstractMetaType)
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(AbstractMetaType::ComparisonFlags);
diff --git a/sources/shiboken2/ApiExtractor/messages.cpp b/sources/shiboken2/ApiExtractor/messages.cpp
index 55c51ffa4..a660f7e76 100644
--- a/sources/shiboken2/ApiExtractor/messages.cpp
+++ b/sources/shiboken2/ApiExtractor/messages.cpp
@@ -649,6 +649,12 @@ QString msgIncorrectlyNestedName(const QString &name)
            + name + QLatin1String(").");
 }
 
+QString msgCannotFindView(const QString &viewedName, const QString &name)
+{
+    return QLatin1String("Unable to find viewed type ") + viewedName
+        + QLatin1String(" for ") + name;
+}
+
 // qtdocgenerator.cpp
 
 QString msgTagWarning(const QXmlStreamReader &reader, const QString &context,
diff --git a/sources/shiboken2/ApiExtractor/messages.h b/sources/shiboken2/ApiExtractor/messages.h
index 6c173dc09..55481270c 100644
--- a/sources/shiboken2/ApiExtractor/messages.h
+++ b/sources/shiboken2/ApiExtractor/messages.h
@@ -179,6 +179,8 @@ QString msgNoRootTypeSystemEntry();
 
 QString msgIncorrectlyNestedName(const QString &name);
 
+QString msgCannotFindView(const QString &viewedName, const QString &name);
+
 QString msgCyclicDependency(const QString &funcName, const QString &graphName,
                             const QVector<const AbstractMetaFunction *> &involvedConversions);
 
diff --git a/sources/shiboken2/ApiExtractor/typedatabase.cpp b/sources/shiboken2/ApiExtractor/typedatabase.cpp
index 6aa5513fa..87f5c49df 100644
--- a/sources/shiboken2/ApiExtractor/typedatabase.cpp
+++ b/sources/shiboken2/ApiExtractor/typedatabase.cpp
@@ -894,6 +894,8 @@ void TypeEntry::formatDebug(QDebug &d) const
     FORMAT_BOOL("stream", m_stream)
     FORMAT_LIST_SIZE("codeSnips", m_codeSnips)
     FORMAT_NONEMPTY_STRING("conversionRule", m_conversionRule)
+    if (m_viewOn)
+       d << ", views=" << m_viewOn->name();
     if (!m_version.isNull() && m_version > QVersionNumber(0, 0))
         d << ", version=" << m_version;
     if (m_revision)
diff --git a/sources/shiboken2/ApiExtractor/typesystem.h b/sources/shiboken2/ApiExtractor/typesystem.h
index fa3eae9fc..00f56c51e 100644
--- a/sources/shiboken2/ApiExtractor/typesystem.h
+++ b/sources/shiboken2/ApiExtractor/typesystem.h
@@ -863,6 +863,12 @@ public:
     void setCustomConversion(CustomConversion* customConversion);
     CustomConversion* customConversion() const;
 
+    // View on: Type to use for function argument conversion, fex
+    // std::string_view -> std::string for foo(std::string_view).
+    // cf AbstractMetaType::viewOn()
+    TypeEntry *viewOn() const { return m_viewOn; }
+    void setViewOn(TypeEntry *v) { m_viewOn = v; }
+
     virtual TypeEntry *clone() const;
 
     void useAsTypedef(const TypeEntry *source);
@@ -898,6 +904,7 @@ private:
     CustomConversion *m_customConversion = nullptr;
     SourceLocation m_sourceLocation; // XML file
     uint m_codeGeneration = GenerateAll;
+    TypeEntry *m_viewOn = nullptr;
     int m_revision = 0;
     int m_sbkIndex = 0;
     Type m_type;
diff --git a/sources/shiboken2/ApiExtractor/typesystemparser.cpp b/sources/shiboken2/ApiExtractor/typesystemparser.cpp
index b71a247f3..7323e01f6 100644
--- a/sources/shiboken2/ApiExtractor/typesystemparser.cpp
+++ b/sources/shiboken2/ApiExtractor/typesystemparser.cpp
@@ -1112,16 +1112,44 @@ bool TypeSystemParser::checkRootElement()
     return ok;
 }
 
-void TypeSystemParser::applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
-                                             QXmlStreamAttributes *attributes) const
+static TypeEntry *findViewedType(const QString &name)
+{
+    const auto range = TypeDatabase::instance()->entries().equal_range(name);
+    for (auto i = range.first; i != range.second; ++i) {
+        switch (i.value()->type()) {
+        case TypeEntry::BasicValueType:
+        case TypeEntry::PrimitiveType:
+        case TypeEntry::ContainerType:
+        case TypeEntry::ObjectType:
+            return i.value();
+        default:
+            break;
+        }
+    }
+    return nullptr;
+}
+
+bool TypeSystemParser::applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
+                                             QXmlStreamAttributes *attributes)
 {
     type->setSourceLocation(SourceLocation(m_currentFile,
                                            reader.lineNumber()));
     type->setCodeGeneration(m_generate);
-    const int revisionIndex =
-        indexOfAttribute(*attributes, u"revision");
-    if (revisionIndex != -1)
-        type->setRevision(attributes->takeAt(revisionIndex).value().toInt());
+    for (int i = attributes->size() - 1; i >= 0; --i) {
+        const auto name = attributes->at(i).qualifiedName();
+        if (name ==  u"revision") {
+            type->setRevision(attributes->takeAt(i).value().toInt());
+        } else if (name == u"view-on") {
+            const QString name = attributes->takeAt(i).value().toString();
+            TypeEntry *views = findViewedType(name);
+            if (views == nullptr) {
+                m_error = msgCannotFindView(name, type->name());
+                return false;
+            }
+            type->setViewOn(views);
+        }
+    }
+    return true;
 }
 
 FlagsTypeEntry *
@@ -1146,7 +1174,8 @@ FlagsTypeEntry *
     }
 
     ftype->setOriginalName(flagName);
-    applyCommonAttributes(reader, ftype, attributes);
+    if (!applyCommonAttributes(reader, ftype, attributes))
+        return nullptr;
 
     QStringList lst = flagName.split(colonColon());
     const QString targetLangFlagName = QStringList(lst.mid(0, lst.size() - 1)).join(QLatin1Char('.'));
@@ -1225,7 +1254,8 @@ SmartPointerTypeEntry *
 
     auto *type = new SmartPointerTypeEntry(name, getter, smartPointerType,
                                            refCountMethodName, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     m_smartPointerInstantiations.insert(type, instantiations);
     return type;
 }
@@ -1238,7 +1268,8 @@ PrimitiveTypeEntry *
     if (!checkRootElement())
         return nullptr;
     auto *type = new PrimitiveTypeEntry(name, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     for (int i = attributes->size() - 1; i >= 0; --i) {
         const auto name = attributes->at(i).qualifiedName();
         if (name == targetLangNameAttribute()) {
@@ -1282,7 +1313,8 @@ ContainerTypeEntry *
         return nullptr;
     }
     auto *type = new ContainerTypeEntry(name, containerType, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     return type;
 }
 
diff --git a/sources/shiboken2/ApiExtractor/typesystemparser.h b/sources/shiboken2/ApiExtractor/typesystemparser.h
index 3eaa74f04..130d8d3d2 100644
--- a/sources/shiboken2/ApiExtractor/typesystemparser.h
+++ b/sources/shiboken2/ApiExtractor/typesystemparser.h
@@ -169,8 +169,8 @@ private:
 
     const TypeEntry *currentParentTypeEntry() const;
     bool checkRootElement();
-    void applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
-                               QXmlStreamAttributes *attributes) const;
+    bool applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
+                               QXmlStreamAttributes *attributes);
     PrimitiveTypeEntry *
         parsePrimitiveTypeEntry(const QXmlStreamReader &, const QString &name,
                                 const QVersionNumber &since, QXmlStreamAttributes *);
diff --git a/sources/shiboken2/doc/typesystem_specifying_types.rst b/sources/shiboken2/doc/typesystem_specifying_types.rst
index 221519541..3b40ef236 100644
--- a/sources/shiboken2/doc/typesystem_specifying_types.rst
+++ b/sources/shiboken2/doc/typesystem_specifying_types.rst
@@ -108,6 +108,7 @@ primitive-type
                 target-name="..."
                 default-constructor="..."
                 preferred-conversion="yes | no" />
+                view-on="..."
         </typesystem>
 
     The **name** attribute is the name of the primitive in C++, the optional,
@@ -139,6 +140,13 @@ primitive-type
     used only for classes declared as primitive types and not for primitive C++
     types, but that depends on the application using *ApiExtractor*.
 
+    The *optional* **view-on** attribute specifies that the type is a view
+    class like std::string_view or QStringView which has a constructor
+    accepting another type like std::string or QString. Since typically
+    no values can be assigned to view classes, no target-to-native conversion
+    can be generated for them. Instead, an instance of the viewed class should
+    be instantiated and passed to functions using the view class
+    for argument types.
 
 .. _namespace:
 
diff --git a/sources/shiboken2/generator/shiboken2/cppgenerator.cpp b/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
index 8e9b480cc..89e97093b 100644
--- a/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
+++ b/sources/shiboken2/generator/shiboken2/cppgenerator.cpp
@@ -2389,6 +2389,8 @@ void CppGenerator::writeTypeCheck(QTextStream &s, const OverloadData *overloadDa
     // This condition trusts that the OverloadData object will arrange for
     // PyInt type to come after the more precise numeric types (e.g. float and bool)
     const AbstractMetaType *argType = overloadData->argType();
+    if (auto viewOn = argType->viewOn())
+        argType = viewOn;
     bool numberType = numericTypes.count() == 1 || ShibokenGenerator::isPyInt(argType);
     QString customType = (overloadData->hasArgumentTypeReplace() ? overloadData->argumentTypeReplaced() : QString());
     bool rejectNull = shouldRejectNullPointerArgument(overloadData->referenceFunction(), overloadData->argPos());
@@ -2419,12 +2421,15 @@ const AbstractMetaType *CppGenerator::getArgumentType(const AbstractMetaFunction
         return nullptr;
     }
 
-    const AbstractMetaType *argType = nullptr;
     QString typeReplaced = func->typeReplaced(argPos);
-    if (typeReplaced.isEmpty())
-        argType = (argPos == 0) ? func->type() : func->arguments().at(argPos-1)->type();
-    else
-        argType = buildAbstractMetaTypeFromString(typeReplaced);
+    if (typeReplaced.isEmpty()) {
+        if (argPos == 0)
+            return func->type();
+        auto argType = func->arguments().at(argPos - 1)->type();
+        return argType->viewOn() ? argType->viewOn() : argType;
+    }
+
+    auto argType = buildAbstractMetaTypeFromString(typeReplaced);
     if (!argType && !m_knownPythonTypes.contains(typeReplaced)) {
         qCWarning(lcShiboken).noquote().nospace()
             << QString::fromLatin1("Unknown type '%1' used as argument type replacement "\
@@ -4804,7 +4809,10 @@ void CppGenerator::writeSignatureInfo(QTextStream &s, const AbstractMetaFunction
             args << QLatin1String("self");
         const AbstractMetaArgumentList &arguments = f->arguments();
         for (const AbstractMetaArgument *arg : arguments)  {
-            QString strArg = arg->type()->pythonSignature();
+            const auto *metaType = arg->type();
+            if (auto viewOn = metaType->viewOn())
+                metaType = viewOn;
+            QString strArg = metaType->pythonSignature();
             if (!arg->defaultValueExpression().isEmpty()) {
                 strArg += QLatin1Char('=');
                 QString e = arg->defaultValueExpression();
diff --git a/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/mapping.py b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/mapping.py
index 4af214c8d..7a93fcbe9 100644
--- a/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/mapping.py
+++ b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/mapping.py
@@ -255,6 +255,7 @@ type_map.update({
     "qreal": float,
     "QSet": typing.Set,
     "QString": str,
+    "QStringView": str,
     "QStringList": StringList,
     "quint16": int,
     "quint32": int,
diff --git a/sources/shiboken2/tests/libsample/virtualmethods.cpp b/sources/shiboken2/tests/libsample/virtualmethods.cpp
index 8f9c8f64d..705835c0b 100644
--- a/sources/shiboken2/tests/libsample/virtualmethods.cpp
+++ b/sources/shiboken2/tests/libsample/virtualmethods.cpp
@@ -63,6 +63,11 @@ const Str & VirtualMethods::returnConstRef() const
     return result;
 }
 
+int VirtualMethods::stringViewLength(std::string_view in) const
+{
+    return int(in.size());
+}
+
 double VirtualDaughter2::virtualMethod0(Point pt, int val, Complex cpx, bool b)
 {
     return 42 + VirtualMethods::virtualMethod0(pt, val, cpx, b);
diff --git a/sources/shiboken2/tests/libsample/virtualmethods.h b/sources/shiboken2/tests/libsample/virtualmethods.h
index 4b2d25805..577f6919e 100644
--- a/sources/shiboken2/tests/libsample/virtualmethods.h
+++ b/sources/shiboken2/tests/libsample/virtualmethods.h
@@ -36,6 +36,9 @@
 #include "libsamplemacros.h"
 #include "strlist.h"
 
+#include <string_view>
+#include <string>
+
 class LIBSAMPLE_API VirtualMethods
 {
 public:
@@ -108,6 +111,8 @@ public:
 
     virtual const Str & returnConstRef() const;
 
+    virtual int stringViewLength(std::string_view in) const;
+
 protected:
     // PYSIDE-1388: Protected hack with final classes (see VirtualFinalDaughter).
     void protectedMethod() {}
diff --git a/sources/shiboken2/tests/samplebinding/typesystem_sample.xml b/sources/shiboken2/tests/samplebinding/typesystem_sample.xml
index e4963721b..66ae6d0a1 100644
--- a/sources/shiboken2/tests/samplebinding/typesystem_sample.xml
+++ b/sources/shiboken2/tests/samplebinding/typesystem_sample.xml
@@ -25,6 +25,7 @@
     <primitive-type name="long long"/>
     <primitive-type name="unsigned long long"/>
     <primitive-type name="std::string"/>
+    <primitive-type name="std::string_view" view-on="std::string"/>
     <primitive-type name="ObjectType::Identifier"/>
 
     <primitive-type name="Foo::HANDLE" target-lang-api-name="PyLong"/>
diff --git a/sources/shiboken2/tests/samplebinding/virtualmethods_test.py b/sources/shiboken2/tests/samplebinding/virtualmethods_test.py
index 2d3198071..07b79c489 100644
--- a/sources/shiboken2/tests/samplebinding/virtualmethods_test.py
+++ b/sources/shiboken2/tests/samplebinding/virtualmethods_test.py
@@ -133,6 +133,11 @@ class VirtualMethodsTest(unittest.TestCase):
         self.assertTrue(eevd.grand_grand_daughter_name_called)
         self.assertEqual(eevd.name().prepend(self.prefix_from_codeinjection), name)
 
+    def testStringView(self):
+        virtual_methods = VirtualMethods()
+        self.assertEqual(virtual_methods.stringViewLength('bla'), 3)
+
+
 class PrettyErrorMessageTest(unittest.TestCase):
     def testIt(self):
         obj = ExtendedVirtualMethods()