Description of problem:
Have a (large, e.g. the F19) repo synced in ./repodata.

Run the script:

#! /usr/bin/python

import librepo

MIRROR="""https://mirrors.fedoraproject.org/metalink?repo=fedora-19&arch=x86_64"""
DESTDIR="./"

if __name__ == "__main__":
    h = librepo.Handle()
    h.destdir = DESTDIR
    h.interruptible = True
    h.url = DESTDIR
    h.repotype = librepo.LR_YUMREPO
    h.mirrorlist = MIRROR
    h.yumdlist = ["primary", "filelists", "prestodelta", "group_gz"]
    h.local = True
    h.perform(librepo.Result())
    print(h.mirrors)

Press Ctrl-C during h.perform(). No KeyboardInterrupt will be raised. The last statement will print None (this verifies we pressed Ctrl+C in the right moment yet the perform() somehow didn't finish correctly).