Fix bare except statements for expected ImportErrors

dkim/__init__.py

@@ -41,14 +41,14 @@ import time
 # only needed for arc
 try:
     from authres import AuthenticationResultsHeader
-except:
+except ImportError:
     pass
 
 # only needed for ed25519 signing/verification
 try:
     import nacl.signing
     import nacl.encoding
-except:
+except ImportError:
     pass
 
 from dkim.canonicalization import (
@@ -68,7 +68,7 @@ from dkim.crypto import (
     )
 try:
     from dkim.dnsplug import get_txt
-except:
+except ImportError:
     def get_txt(s):
         raise RuntimeError("DKIM.verify requires DNS or dnspython module")
 from dkim.util import (