Following is the code to git add, git commit and then git push using GitPython.

Install GitPython using pip install gitpython.

from git import Repo

PATH_OF_GIT_REPO = r'path\to\your\project\folder\.git'  # make sure .git folder is properly configured
COMMIT_MESSAGE = 'comment from python script'

def git_push():
    try:
        repo = Repo(PATH_OF_GIT_REPO)
        repo.git.add(update=True)
        repo.index.commit(COMMIT_MESSAGE)
        origin = repo.remote(name='origin')
        origin.push()
    except:
        print('Some error occured while pushing the code')    

git_push()

from git import Repo,remote

rw_dir = 'path/to/your/local/repo'
repo = Repo(rw_dir)

'''Enter code to commit the repository here.
After commit run the following code to push the commit to remote repo.
I am pushing to master branch here'''

origin = repo.remote(name='origin')
origin.push()

To do it from macOS (Mac terminal) using the shell from python, you can do this:

#Import dependencies
from subprocess import call

#Commit Message
commit_message = "Adding sample files"

#Stage the file 
call('git add .', shell = True)

# Add your commit
call('git commit -m "'+ commit_message +'"', shell = True)

#Push the new or update files
call('git push origin master', shell = True)

What you need to do is to use git directly. This is explained at the end of the gitpython tutorial.

Basically, when you have a repo object, you can call every git function like

repo.git.function(param1, param2, param3, ...) 

so for example, to call the git command

git push --set-upstream origin testbranch

you do

repo.git.push("--set-upstream", "origin", "testbranch")

Special rules concerning '-' applies.

So the full sequence, in order to create a new branch and push it to github, becomes

repo = Repo('Repos/hello-world/.git')
# make changes to README.md
repo.index.add('README.md')
repo.index.commit("My commit message")
repo.git.checkout("-b", "new_branch")
repo.git.push("--set-upstream","origin","new_branch")

How you create a pull request on github for the new branch, is some different magic I do not master yet...

How do I push new files to GitHub?

A very similar question who's code I was able to modify to make multiple file pushes to github via python:

import base64
from github import Github
from github import InputGitTreeElement

user = "GithubUsername"
password = "*********"
g = Github(user,password)
repo = g.get_user().get_repo('git-test') # repo name
file_list = [
    'C:\\Users\jesse\Dropbox\Swell-Forecast\git-test\index.html',
    'C:\\Users\jesse\Dropbox\Swell-Forecast\git-test\margin_table.html'
]
file_names = [
    'index.html',
    'margin_table.html'
]
commit_message = 'python commit'
master_ref = repo.get_git_ref('heads/master')
master_sha = master_ref.object.sha
base_tree = repo.get_git_tree(master_sha)

element_list = list()
for i, entry in enumerate(file_list):
    with open(entry) as input_file:
        data = input_file.read()
    if entry.endswith('.png'): # images must be encoded
        data = base64.b64encode(data)
    element = InputGitTreeElement(file_names[i], '100644', 'blob', data)
    element_list.append(element)

tree = repo.create_git_tree(element_list, base_tree)
parent = repo.get_git_commit(master_sha)
commit = repo.create_git_commit(commit_message, tree, [parent])
master_ref.edit(commit.sha)