diff --git a/src/if_py_both.h b/src/if_py_both.h
index 3ab1851..0031003 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -2530,8 +2530,10 @@
 #if PY_MAJOR_VERSION >= 3
     else if (PyBytes_Check(obj))
     {
-	char_u	*result = (char_u *) PyBytes_AsString(obj);
+	char_u	*result;
 
+	if (PyString_AsStringAndSize(obj, (char **) &result, NULL) == -1)
+	    return -1;
 	if (result == NULL)
 	    return -1;
 
@@ -2549,7 +2551,8 @@
 	if (bytes == NULL)
 	    return -1;
 
-	result = (char_u *) PyBytes_AsString(bytes);
+	if(PyString_AsStringAndSize(bytes, (char **) &result, NULL) == -1)
+	    return -1;
 	if (result == NULL)
 	    return -1;
 
@@ -2572,7 +2575,8 @@
 	if (bytes == NULL)
 	    return -1;
 
-	result=(char_u *) PyString_AsString(bytes);
+	if(PyString_AsStringAndSize(bytes, (char **) &result, NULL) == -1)
+	    return -1;
 	if (result == NULL)
 	    return -1;
 
@@ -2587,8 +2591,10 @@
     }
     else if (PyString_Check(obj))
     {
-	char_u	*result = (char_u *) PyString_AsString(obj);
+	char_u	*result;
 
+	if(PyString_AsStringAndSize(obj, (char **) &result, NULL) == -1)
+	    return -1;
 	if (result == NULL)
 	    return -1;