Issue #16922: fixed findtext() to return empty Unicode string instead of empty bytes object when there's no text.

Patch by Serhiy Storchaka.
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
index 59a8508..b4edd74 100644
--- a/Lib/test/test_xml_etree.py
+++ b/Lib/test/test_xml_etree.py
@@ -1773,6 +1773,9 @@
         self.assertIsNone(e.findtext('tog'))
         self.assertEqual(e.findtext('tog', 'default'), 'default')
 
+        # Issue #16922
+        self.assertEqual(ET.XML('<tag><empty /></tag>').findtext('empty'), '')
+
     def test_findall(self):
         e = ET.XML(SAMPLE_XML)
         e[2] = ET.XML(SAMPLE_SECTION)
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 274c65e..49441cc 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -1129,7 +1129,7 @@
 
             PyObject* text = element_get_text(item);
             if (text == Py_None)
-                return PyBytes_FromString("");
+                return PyUnicode_New(0, 0);
             Py_XINCREF(text);
             return text;
         }