Datetime fix

README.md

@@ -456,7 +456,7 @@ from itertools import product, combinations, combinations_with_replacement, perm
 
 Datetime
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-* **Module 'datetime' provides 'date' `<D>`, 'time' `<T>`, 'datetime' `<DT>` and 'timedelta' `<TD>` classes, all of which are immutable and hashable.**
+* **Module 'datetime' provides 'date' `<D>`, 'time' `<T>`, 'datetime' `<DT>` and 'timedelta' `<TD>` classes. All are immutable and hashable.**
 * **Time and datetime can be 'aware' `<a>`, meaning they have defined timezone, or 'naive' `<n>`, meaning they don't.**
 * **If object is naive it is presumed to be in system's timezone.**