Here is the terminal output of what I did to remove the file from the git history:

~/g/aliostad bfg --delete-files 1703 deep-learning-lang-detection.git

Using repo : /Users/alikheyrollahi/github/aliostad/deep-learning-lang-detection.git

Found 72811 objects to protect
Found 2 commit-pointing refs : HEAD, refs/heads/master

Protected commits
-----------------

These are your protected commits, and so their contents will NOT be altered:

* commit ac12aa68 (protected by 'HEAD') - contains 8 dirty files :
- data/stackoverflow-snippets/cpp/1703 (3.0 KB)
- data/stackoverflow-snippets/csharp/1703 (835 B)
- ...

WARNING: The dirty content above may be removed from other commits, but as
the protected commits still use it, it will STILL exist in your repository.

Details of protected dirty content have been recorded here :

/Users/alikheyrollahi/github/aliostad/deep-learning-lang-detection.git.bfg-report/2020-01-27/22-24-03/protected-dirt/

If you really want this content gone, make a manual commit that removes it,
and then run the BFG on a fresh copy of your repo.

Cleaning
--------

Found 69 commits
Cleaning commits: 100% (69/69)
Cleaning commits completed in 304 ms.

Updating 1 Ref
--------------

Ref Before After
---------------------------------------
refs/heads/master | ac12aa68 | c51406cc

Updating references: 100% (1/1)
...Ref update completed in 13 ms.

Commit Tree-Dirt History
------------------------

Earliest Latest
| |
.................................................DDDDDDDDDDm

D = dirty commits (file tree fixed)
m = modified commits (commit message or parents changed)
. = clean commits (no changes to file tree)

Before After
-------------------------------------------
First modified commit | a4a1bbac | cb32cfbf
Last dirty commit | 45322921 | 6b9e8d5d

Deleted files
-------------

Filename Git id
---------------------------------------------------
1703 | 530293d7 (614 B), 98c9b646 (3.0 KB), ...

In total, 47 object ids were changed. Full details are logged here:

/Users/alikheyrollahi/github/aliostad/deep-learning-lang-detection.git.bfg-report/2020-01-27/22-24-03

BFG run is complete! When ready, run: git reflog expire --expire=now --all && git gc --prune=now --aggressive

--
You can rewrite history in Git - don't let Trump do it for real!
Trump's administration has lied consistently, to make people give up on ever
being told the truth. Don't give up: https://www.aclu.org/
--

~/g/aliostad cd deep-learning-lang-detection.git
~/g/a/deep-learning-lang-detection.git git reflog expire --expire=now --all && git gc --prune=now --aggressive
Enumerating objects: 89539, done.
Counting objects: 100% (89539/89539), done.
Delta compression using up to 8 threads
Compressing objects: 100% (89537/89537), done.
Writing objects: 100% (89539/89539), done.
Total 89539 (delta 28336), reused 61123 (delta 0)
~/g/a/deep-learning-lang-detection.git git push
Enter passphrase for key '/Users/alikheyrollahi/.ssh/id_rsa':
Enumerating objects: 89539, done.
Counting objects: 100% (89539/89539), done.
Delta compression using up to 8 threads
Compressing objects: 100% (61201/61201), done.
Writing objects: 100% (89539/89539), 40.83 MiB | 1.01 MiB/s, done.
Total 89539 (delta 28336), reused 89539 (delta 28336)
remote: Resolving deltas: 100% (28336/28336), done.
To github.com:aliostad/deep-learning-lang-detection.git
+ ac12aa680...c51406cc8 master -> master (forced update)
~/g/a/deep-learning-lang-detection.git cd ..