Replaced outdated macros _PyUnicode_AsString and _PyUnicode_AsStringAndSize
with PyUnicode_AsUTF8 and PyUnicode_AsUTF8AndSize.
diff --git a/Modules/_io/stringio.c b/Modules/_io/stringio.c
index ecf6dc1..8542efd 100644
--- a/Modules/_io/stringio.c
+++ b/Modules/_io/stringio.c
@@ -708,7 +708,7 @@
                          Py_TYPE(newline_obj)->tp_name);
             return -1;
         }
-        newline = _PyUnicode_AsString(newline_obj);
+        newline = PyUnicode_AsUTF8(newline_obj);
         if (newline == NULL)
             return -1;
     }
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 2f55eb0..1c7200b 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -921,7 +921,7 @@
             Py_CLEAR(self->encoding);
     }
     if (self->encoding != NULL) {
-        encoding = _PyUnicode_AsString(self->encoding);
+        encoding = PyUnicode_AsUTF8(self->encoding);
         if (encoding == NULL)
             goto error;
     }
@@ -964,7 +964,7 @@
     }
     self->writetranslate = (newline == NULL || newline[0] != '\0');
     if (!self->readuniversal && self->readnl) {
-        self->writenl = _PyUnicode_AsString(self->readnl);
+        self->writenl = PyUnicode_AsUTF8(self->readnl);
         if (self->writenl == NULL)
             goto error;
         if (!strcmp(self->writenl, "\n"))