socket.error inherits from IOError, it no longer needs listing in

the all_errors tuple.

Lib/ftplib.py

@@ -65,7 +65,7 @@ class error_proto(Error): pass          # response does not begin with [1-5]
 
 # All exceptions (hopefully) that may be raised here and that aren't
 # (always) programming errors on our side
-all_errors = (Error, socket.error, IOError, EOFError)
+all_errors = (Error, IOError, EOFError)
 
 
 # Line terminators (we always output CRLF, but accept any of CRLF, CR, LF)