all: Make more use of mp_raise_{msg,TypeError,ValueError} helpers.
diff --git a/py/stream.c b/py/stream.c
index d3fc767..0186099 100644
--- a/py/stream.c
+++ b/py/stream.c
@@ -142,7 +142,7 @@
         while (more_bytes > 0) {
             char *p = vstr_add_len(&vstr, more_bytes);
             if (p == NULL) {
-                nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_MemoryError, "out of memory"));
+                mp_raise_msg(&mp_type_MemoryError, "out of memory");
             }
             int error;
             mp_uint_t out_sz = mp_stream_read_exactly(args[0], p, more_bytes, &error);
@@ -381,7 +381,7 @@
     while (max_size == -1 || max_size-- != 0) {
         char *p = vstr_add_len(&vstr, 1);
         if (p == NULL) {
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_MemoryError, "out of memory"));
+            mp_raise_msg(&mp_type_MemoryError, "out of memory");
         }
 
         int error;