Apply suggestions from code review

Co-authored-by: Victor Stinner <vstinner@python.org>

Author: marcelm

Lib/test/test_io/test_memoryio.py

@@ -568,7 +568,7 @@ def test_issue141311(self):
 
     def test_peek(self):
         buf = self.buftype("1234567890")
-        with  self.ioclass(buf) as memio:
+        with self.ioclass(buf) as memio:
             self.assertEqual(memio.tell(), 0)
             self.assertEqual(memio.peek(1), buf[:1])
             self.assertEqual(memio.peek(1), buf[:1])

Modules/_io/bytesio.c

@@ -452,6 +452,7 @@ read_bytes_lock_held(bytesio *self, Py_ssize_t size)
 {
     PyObject *bytes = peek_bytes_lock_held(self, size);
     if (bytes != NULL) {
+        assert(PyBytes_GET_SIZE(bytes) == size);
         self->pos += size;
     }
     return bytes;
@@ -539,7 +540,6 @@ _io_BytesIO_peek_impl(bytesio *self, Py_ssize_t size)
 }
 
 
-
 /*[clinic input]
 @critical_section
 _io.BytesIO.readline