Update Testing/Python.rst (#4408) (#4411)

(cherry picked from commit fa24440)

Co-authored-by: Jasmeet Singh <[email protected]>

Author: mergify[bot]

source/Tutorials/Intermediate/Testing/Python.rst

@@ -14,7 +14,7 @@ Package Setup
 setup.py
 ^^^^^^^^
 
-Your ``setup.py`` must a test dependency on ``pytest`` within the call to ``setup(...)``:
+Your ``setup.py`` must have a test dependency on ``pytest`` within the call to ``setup(...)``:
 
 .. code-block:: python