example broken due to missing FTP files

[thekswenson]

The example in the Jupyter notebook cannot be followed because the file is not found:

=> wget ftp://cooler.csail.mit.edu/coolers/hg19/Rao2014-GM12878-MboI-allreps-filtered.5kb.cool
--2023-05-03 14:50:37--  ftp://cooler.csail.mit.edu/coolers/hg19/Rao2014-GM12878-MboI-allreps-filtered.5kb.cool
           => ‘Rao2014-GM12878-MboI-allreps-filtered.5kb.cool’
Resolving cooler.csail.mit.edu (cooler.csail.mit.edu)... 128.52.129.246
Connecting to cooler.csail.mit.edu (cooler.csail.mit.edu)|128.52.129.246|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /coolers/hg19 ... 
No such directory ‘coolers/hg19’.