Update README.md

README.md

 
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 ### Part 10.0 - Test refactored classes.
-* Ensure that the `TestStudents`, `TestInstructors`, `TestPeople`, `TestZipCodeWilmington` classes were no affected by the refactor.
+* Ensure that the `TestStudents`, `TestInstructors`, `TestPeople`, `TestZipCodeWilmington` classes were not affected by the refactor.