diff -urN a/Include/cpython/unicodeobject.h b/Include/cpython/unicodeobject.h
--- a/Include/cpython/unicodeobject.h	2022-03-16 16:03:13.000000000 +0300
+++ b/Include/cpython/unicodeobject.h	2022-03-29 17:11:43.669283292 +0300
@@ -876,6 +876,23 @@
                                               string. */
 );
 
+/*
+ * START Anaconda (tkoch):
+ *
+ * For compatibility with packages like typed_ast and mypy compiled against
+ * Python 3.9.7.
+ */
+PyAPI_FUNC(PyObject*) _PyUnicode_DecodeUnicodeEscape(
+        const char *string,     /* Unicode-Escape encoded string */
+        Py_ssize_t length,      /* size of string */
+        const char *errors,     /* error handling */
+        const char **first_invalid_escape  /* on return, points to first
+                                              invalid escaped char in
+                                              string. */
+);
+
+/* Anaconda END */
+
 Py_DEPRECATED(3.3) PyAPI_FUNC(PyObject*) PyUnicode_EncodeUnicodeEscape(
     const Py_UNICODE *data,     /* Unicode char buffer */
     Py_ssize_t length           /* Number of Py_UNICODE chars to encode */
diff -urN a/Objects/unicodeobject.c b/Objects/unicodeobject.c
--- a/Objects/unicodeobject.c	2022-03-16 16:03:13.000000000 +0300
+++ b/Objects/unicodeobject.c	2022-03-29 16:53:44.755537475 +0300
@@ -6539,6 +6539,37 @@
     return _PyUnicode_DecodeUnicodeEscapeStateful(s, size, errors, NULL);
 }
 
+/*
+ * START Anaconda (tkoch):
+ *
+ * For compatibility with packages like typed_ast and mypy compiled against
+ * Python 3.9.7.
+ */
+PyObject *
+_PyUnicode_DecodeUnicodeEscape(const char *s,
+                               Py_ssize_t size,
+                               const char *errors,
+                               const char **first_invalid_escape)
+{
+    Py_ssize_t consumed;
+    PyObject *result = _PyUnicode_DecodeUnicodeEscapeInternal(s, size, errors,
+                                                      &consumed,
+                                                      first_invalid_escape);
+    if (result == NULL)
+        return NULL;
+    if (*first_invalid_escape != NULL) {
+        if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
+                             "invalid escape sequence '\\%c'",
+                             (unsigned char)**first_invalid_escape) < 0) {
+            Py_DECREF(result);
+            return NULL;
+        }
+    }
+    return result;
+}
+
+/* Anaconda END */
+
 /* Return a Unicode-Escape string version of the Unicode object. */
 
 PyObject *