Apply ruff/pyupgrade rule UP035

UP035 Import from `collections.abc` instead: `Callable`

Co-authored-by: Matti Picus <[email protected]>

Author: DimitriPapadopoulos

src/cffi/api.py

@@ -3,13 +3,6 @@
 from .error import CDefError
 from . import model
 
-try:
-    callable
-except NameError:
-    # Python 3.1
-    from collections import Callable
-    callable = lambda x: isinstance(x, Callable)
-
 try:
     basestring
 except NameError: