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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def git_remote(git_repo):
 """Return the URL for remote git repository. Depending on the system setup it returns ssh or https remote. """

    github_token = os.getenv(GITHUB_TOKEN_KEY)
    if github_token:
        return 'https://{0}@github.com/{1}'.format(
            github_token, git_repo)
    return 'git@github.com:{0}'.format(git_repo)