Reject the idea of using 'def' as a keyword.

pep-0526.txt

@@ -435,6 +435,17 @@ Rejected proposals and things left out for now
   globals. Second, no matter what we choose, we'd still need
   a ``__future__`` import.
 
+- **Use 'def' as a keyword:**
+  The proposal would be::
+
+    def primes: List[int] = []
+    def captain: str
+
+  The problem with this is that ``def`` means "define a function" to
+  generations of Python programmers (and tools!), and using it also to
+  define variables does not increase clarity.  (Though this is of
+  course subjective.)
+
 - **Allow type annotations for tuple unpacking:**
   This causes an ambiguity: It's not clear what meaning should be
   assigned to this statement::