Remove duplication.
diff --git a/Doc/howto/pyporting.rst b/Doc/howto/pyporting.rst
index 124ef33..309f3f7 100644
--- a/Doc/howto/pyporting.rst
+++ b/Doc/howto/pyporting.rst
@@ -328,7 +328,7 @@
textual data, people have over the years been rather loose in their delineation
of what ``str`` instances held text compared to bytes. In Python 3 you cannot
be so care-free anymore and need to properly handle the difference. The key
-handling this issue to to make sure that **every** string literal in your
+handling this issue to make sure that **every** string literal in your
Python 2 code is either syntactically of functionally marked as either bytes or
text data. After this is done you then need to make sure your APIs are designed
to either handle a specific type or made to be properly polymorphic.