netrc.netrc() throws a NetrcParseError if ~/.netrc contains an entry witout a 'password' field.  Other users of .netrc do not do this.  In my case, I have entries for sftp hosts which will use public-key authentication instead of a password.

What I would suggest is that if any or all of 'login', 'account', and 'password' are omitted, simply accept that and store a 0-length string.

Someone on StackOverflow says he has rewritten netrc to fix various problems but doesn't know how to contribute it.  http://stackoverflow.com/questions/28754547/python-netrc-error-on-file-with-comment