Fix pylint errors

Author: tekktrik

adafruit_rsa/key.py

@@ -58,8 +58,6 @@
 class AbstractKey(object):
     """Abstract superclass for private and public keys."""
 
-    __slots__ = ("n", "e")
-
     def __init__(self, n: int, e: int) -> None:
         self.n = n
         self.e = e

adafruit_rsa/pkcs1.py

@@ -44,7 +44,6 @@ class _FileLikeObject(Protocol):
 
         def read(self, blocksize: int) -> Union[bytes, str]:
             """A method that reads a given number of bytes or chracters"""
-            ...
 
 except ImportError:
     pass

examples/rsa_tests.py

@@ -93,11 +93,10 @@ def test_sign_verify_fail():
 
 # Run adafruit_rsa tests
 start_time = time.monotonic()
-# pylint: disable=consider-using-enumerate
-for test_num, test_name in enumerate(all_tests, start=0):
+for test_name in all_tests:
     # for i in range(0, len(all_tests)):
     print("Testing: {}".format(test_name))
-    all_tests[test_num]()
+    test_name()
     print("OK!")
 print(
     "Ran {} tests in {} seconds".format(len(all_tests), time.monotonic() - start_time)