filter the OPML, which was imported to Feedeen, using its import notification mail.

filteropml.py

# coding: utf-8
from __future__ import print_function
import sys
import xml.etree.ElementTree as ET
import urllib.request
import html

def remove_node(root, node):
    title = html.escape(node.attrib['title'])
    for parent in root.findall('.//outline[@title="{}"]/..'.format(title)):
        if parent.findall('outline[@title="{}"]'.format(title)) == [node]:
            parent.remove(outline)

titleset = set()
for l in sys.stdin:
    titleset.add(l.strip())

opml = sys.argv[1]
tree = ET.parse(opml)
root = tree.getroot()


for outline in root.findall('.//outline[@type="rss"]'):
    title = html.escape(outline.attrib['title'])
    url = outline.attrib['xmlUrl']
    print('title = {}, url={}'.format(title, url), file=sys.stderr)
    if title not in titleset:
        remove_node(root, outline)
    else:
        try:
            with urllib.request.urlopen(url) as f:
                print("{}: {}".format(url, f.status), file=sys.stderr)
        except Exception as ex:
            print("{} {}".format(ex, url), file=sys.stderr)
            remove_node(root, outline)

tree.write(sys.stdout.buffer, encoding='utf-8')

gistfile1.sh

python -c 'import sys,email;print(str(email.message_from_file(sys.stdin).get_payload(decode=1),"utf-8"))' < mail.txt  | sed -n 's/^ \* //p' | python filteropml.py subscriptions.xml > newopml.xml

# mail.txt is the orignal mail from feedeen(Content-Type: text/plain; charset=UTF-8 and Content-Transfer-Encoding: base64)
# if you have a decoded mail body, do not need the mail decode process on the first.
# subscriptions.xml is the OPML you want to import