From 5a501d656d4159b2f3136304dd5544d0a66a203a Mon Sep 17 00:00:00 2001
From: Simon Hawkins <simonjayhawkins@gmail.com>
Date: Wed, 20 Nov 2019 17:31:22 +0000
Subject: [PATCH] CI: fix imminent mypy failure

---
 pandas/io/pytables.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pandas/io/pytables.py b/pandas/io/pytables.py
index 4c9e10e0f4601..7c447cbf78677 100644
--- a/pandas/io/pytables.py
+++ b/pandas/io/pytables.py
@@ -2044,6 +2044,8 @@ def convert(
             the underlying table's row count are normalized to that.
         """
 
+        assert self.table is not None
+
         _start = start if start is not None else 0
         _stop = min(stop, self.table.nrows) if stop is not None else self.table.nrows
         self.values = Int64Index(np.arange(_stop - _start))